An introduction to the study of fishes

by Albert C. L. G. Günther

SECOND SUB-CLASS—TELEOSTEI.

Heart with a non-contractile bulbus arteriosus; intestine without spiral valve; optic nerves decussating; skeleton ossified, with completely formed vertebræ; vertebral column diphycercal or homocercal; branchiæ free.[40]

The Teleostei form the majority of the fishes of the present fauna, and are the geological successors of the Palæichthyes, undoubted Teleostei not ranging farther back than the Chalk. This sub-class comprises an infinite variety of forms; and as, naturally, many Ganoid fishes lived under similar external conditions, and led a similar mode of life as certain Teleostei, we find not a few analogous forms in both series: some Ganoids resembling externally the Teleosteous Siluroids, others the Clupeoids, others the Chætodonts, others the Scombresoces, etc. But there is no direct genetic relation between those fishes, as some Naturalists were inclined to believe.

The Teleostei are divided into six orders:—

A. Acanthopterygii.—Part of the rays of the dorsal, anal, and ventral fins not articulated, spines. The lower pharyngeals separate. Air-bladder, if present, without pneumatic duct in the adult.

B. Acanthopterygii pharyngognathi.—Part of the rays of the dorsal, anal, and ventral fins not articulated, spines. The lower pharyngeals coalesced. Air-bladder without pneumatic duct.

C. Anacanthini.—Vertical and ventral fins without spinous rays. Ventral fins, if present, jugular or thoracic. Air-bladder, if present, without pneumatic duct. Lower pharyngeals separate.

D. Physostomi.—All the fin rays articulated; only the first of the dorsal and pectoral fins is sometimes ossified. Ventral fins, if present, abdominal, without spine. Air-bladder, if present, with a pneumatic duct.

E. Lophobranchii.—Gills not laminated, but composed of small rounded lobes, attached to the branchial arches. Gill-cover reduced to a large simple plate. A dermal skeleton replaces more or less soft integuments.

F. Plectognathi.—A soft dorsal fin opposite to the anal; sometimes elements of a spinous dorsal. Ventral fins none, or reduced to spines. Gills pectinate; air-bladder without pneumatic duct. Skin with rough scutes, or with spines, or naked.

FIRST ORDER—ACANTHOPTERYGII.

Part of the rays of the dorsal, anal, and ventral fins are not articulated, more or less pungent spines. The lower pharyngeals are generally separate. Air-bladder, if present, without pneumatic duct in the adult.[41]

First Division—Acanthopterygii Perciformes.

Body more or less compressed, elevated or oblong, but not elongate; the vent is remote from the extremity of the tail, behind the ventral fins if they are present. No prominent anal papilla. No superbranchial organ. Dorsal fin or fins occupying the greater portion of the back; spinous dorsal well developed, generally with stiff spines, of moderate extent, rather longer than, or as long as, the soft; the soft anal similar to the soft dorsal, of moderate extent or rather short. Ventrals thoracic, with one spine and with four or five rays.

First Family—Percidæ.

The scales extend but rarely over the vertical fins, and the lateral line is generally present, continuous from the head to the caudal fin. All the teeth simple and conical; no barbels. No bony stay for the præoperculum.

A large family, represented by numerous genera and species in fresh waters, and on all the coasts of the temperate and tropical regions. Carnivorous.

Fossil Percoids abound in some formations, for instance, at Monte Bolca, where species of Labrax, Lates, Smerdis and Cyclopoma (both extinct), Dules, Serranus, Apogon, Therapon, and Pristipoma have been recognised. Paraperca is a genus recently discovered in the Marles of Aix-en-Provence. A species of Perca is known from the freshwater deposit of Oeningen.

Perca.—All the teeth are villiform, without canines; teeth on the palatine bones and vomer; tongue toothless. Two dorsal fins, the first with thirteen or fourteen spines; anal fin with two spines. Præoperculum and præorbital serrated. Scales small; head naked above. Branchiostegals seven. Vertebræ more than twenty-four.

The “Freshwater Perch” (Perca fluviatilis) is too familiarly known to require description. It is generally distributed over Europe and Northern Asia; and equally common in North America, there being no sufficient ground for separating specifically the specimens of the Western Hemisphere. It frequents especially still waters, and sometimes descends into brackish water. Its weight does not seem to exceed 5 lbs. The female deposits her ova, united together by a viscid matter, in lengthened or net-shaped bands, on waterplants. The number of the eggs of one spawn may exceed a million. Two other species, P. gracilis, from Canada, and P. schrenckii, from Turkestan, have been distinguished, but they are very imperfectly known. An allied genus is Siniperca, from Northern China.

Fig. 151.—Perca fluviatilis, the Perch.

Percichthys.—Differing from Perca especially in the number of the fin-spines, which are nine or ten in the first dorsal, and three in the anal fin. The upper surface of the head scaly.

These fishes represent the Freshwater Perches of the Northern Hemisphere in the fresh waters of the temperate parts of South America. Two species have been described from Patagonia, and one or two from Chili and Peru.

Labrax.—All the teeth are villiform, without canines; teeth on the palatine bones, vomer, and the tongue. Two dorsal fins, the first with nine spines; anal fin generally with three. Præoperculum serrated, and with denticulations along its lower limb; præorbital with the margin entire. Scales rather small. Branchiostegals seven; well developed pseudobranchiæ.

The “Bass” are fishes common on the coasts of Europe and the Atlantic coasts, and in the fresh waters of the United States and Canada. The three European species are almost exclusively inhabitants of the sea, entering brackish, but never fresh waters, whilst the American species, the number of which is still uncertain, seem to affect principally fresh water, although some are also found in the sea. The best known European species is Labrax lupus (see p. 41, Fig. [4]), common on the British coasts. It is a voracious fish, with a remarkably large stomach, and received from the ancient Romans the appropriate name of lupus. By the Greeks it was so highly esteemed that Archestratus termed this or one of the two other closely-allied species, taken near Milet, “offspring of the gods.” They attributed to it a tender regard for its own safety; and Aristotle says that it is the most cunning of fishes; and that, when surrounded by the net, it digs for itself a channel of escape through the sand. Specimens of from two to three feet are not scarce, but its flesh is nowadays much less esteemed than in ancient times. Of the North American species Labrax lineatus and Labrax rufus are the most common.

Lates.—All the teeth are villiform, without canines; teeth on the palatine bones and vomer, but none on the tongue. Two dorsal fins—the first with seven or eight, the anal fin with two or three, spines. Præoperculum with strong spines at the angle and the lower limb; also the præorbital is strongly serrated. Scales of moderate size. Branchiostegals seven; pseudobranchiæ present.

Three well-known species belong to this genus. The Perch of the Nile and other rivers of tropical Africa (Lates niloticus); the Perch of the Ganges and other East Indian rivers, which enters freely brackish water, and extends to the rivers of Queensland (Lates calcarifer). These two species attain to a large size, the Indian species to a length of five feet. Hamilton says that “the vulgar English in Calcutta call it ‘Cockup,’ and that it is one of the lightest and most esteemed foods brought to table in that city.” Specimens two feet in length and caught in salt water are by far the best quality. The third species (Lates colonorum) is found in Australia only, and does not appear to grow to the same large size as its congeners.

Allied to Lates is Psammoperca from Australia.

Percalabrax.—All the teeth villiform, without canines; teeth on the palatine bones and vomer, but none on the tongue. Two dorsal fins—the first with eleven, the anal fin with three spines. Præoperculum serrated along its hinder margin, and with strong spinous teeth below; præorbital not serrated. Scales rather small. Branchiostegals seven; pseudobranchiæ present.

This Perch (Percalabrax japonicus) is one of the most common fishes on the coasts of China, Japan, and Formosa; the Japanese name it “Zuzuki,” or “Seengo.”

Acerina.—All the teeth villiform, without canines; teeth on the vomer, but none on the palatine bones or the tongue. One continuous dorsal fin, of which the spinous portion consists of from thirteen to nineteen spines; two anal spines. Body rather low, with rather small scales. Bones of the skull with wide muciferous cavities; præoperculum denticulated.

Small freshwater perches, of which A. cernua, named “Pope” in England, is the most common, and has the widest distribution in Central Europe and Siberia. The two other species have a more restricted range, A. schrætzer being confined to the Danube and other rivers emptying into the Black Sea; and A. czekanowskii to Siberian rivers. This genus is not represented in the Western Hemisphere.

Lucioperca.—Teeth in villiform bands, those in the jaws with additional canines; palatine bones toothed. Two dorsal fins—the first with from twelve to fourteen, the anal fin with two spines. Præoperculum serrated; scales small.

The “Pike-Perches” are inhabitants of many lakes and rivers of the temperate northern zone. The European species is confined to the eastern two-thirds of the continent, and one of the most esteemed freshwater fishes; it attains to a length of three or four feet, and to a weight of from 25 to 30 lbs. It has been recommended for acclimatisation in England, and there is no doubt that in certain localities it might prove a valuable addition to the native fauna; but like all its congeners it is very voracious and destructive to smaller fishes. Two other species inhabit rivers of European and Asiatic Russia, and two or three the fresh waters of North America.

Pileoma.—All the teeth minute, villiform, without canines; teeth on the vomer and palatine bones. Two dorsal fins—the first with fourteen or fifteen spines. Body rather elongate, with small scales. Præoperculum not serrated.

Small freshwater perches abundant in the United States. Like the following genus, and some others which need not be mentioned here, they can be regarded as small, dwarfed representatives of the preceding genera. The species seem to be numerous, but have not yet been sufficiently well distinguished. The latest and best account of them is by L. Vaillant, “Recherches sur les Poissons d’eaux douces de l’Amérique septentrionale (Etheostomatidæ),” in Nouv. Archiv. du Muséum d’Hist. Nat. de Paris, ix., 1873.

Boleosoma.—Allied to Pileoma, but with only nine or ten feeble spines in the first dorsal fin. North America.

Aspro.—Body elongate, cylindrical; snout thick, projecting beyond the mouth, which is situated at its lower side. All the teeth villiform, without canines; teeth on the vomer and palatine bones. Two separate dorsals. Præoperculum serrated; præorbital entire. Scales small.

Two small Perches from the Danube and some other rivers of the continent of Europe, Aspro vulgaris and A. zingel.

Centropomus.—Body oblong, compressed, with scales of moderate size. All the teeth villiform, without canines; teeth on the vomer and palatine bones. Two dorsal fins, the first with eight strong spines, the anal with three, the second of which is very strong and long. Præoperculum with a double denticulated edge.

Numerous species are known from the West Indies and Central America. These fishes are found in fresh, brackish, and salt water, and some of the species indiscriminately enter all three kinds of water. They do not grow to any large size, but are esteemed as food.

Enoplosus.—Body much elevated, the depth being still more increased by the high vertical fins. All the teeth are villiform, without canines; teeth on the vomer, palatine bones, and the tongue. Two dorsal fins, the first with seven spines. Præoperculum serrated, with spinous teeth at the angle. Scales of moderate size.

A small and very common marine species (E. armatus) on the coast of Australia, especially New South Wales. It is readily recognised by the peculiar shape of its body, and eight black transverse bands on a whitish ground.

---

This, and the preceding genus, leads to the true “Sea perches,” which never, or but rarely, enter fresh water:—

Centropristis.—Body oblong, with scales of small or moderate size. Teeth villiform, with small canines in both jaws; vomerine teeth placed in an angular band, or a short triangular patch; teeth on the palatine bones, but none on the tongue. One dorsal, with the formula 10/12 or less; anal fin 3/7(6). Præoperculum serrated; sometimes with the angle projecting, and armed with long spines.

About twenty species of small size are known from temperate and tropical seas.

Anthias.—Body rather short, compressed, with scales of moderate size. Teeth villiform, with small canines in both jaws; teeth on the vomer, and palatine teeth. One dorsal, generally with ten spines; anal fin with three; caudal forked. The rays of one or more fins may be prolonged. Præoperculum serrated.

About twenty species are known from temperate and tropical seas; they are mostly of small size, and agreeably coloured, pink and yellow being the predominant colours. Anthias sacer is common in the Mediterranean, and was well known to the ancients. Aristotle says that the fishers of Sponges call it sacred, because no voracious fishes came to the places which it frequented, and the diver might descend with safety.—Callanthias is a genus closely allied to Anthias.

Serranus.—Body oblong, compressed, with small scales. Teeth villiform, with very distinct canines in both jaws; teeth on the vomer and palatine bones, none on the tongue. One dorsal, mostly with nine or eleven, rarely with eight, ten or twelve spines; anal fin with three: all the spines being stout. Præoperculum serrated behind and at the angle, but not below.

Fig. 152.—Serranus altivelis.

The “Sea perches proper” are found on the shores of all temperate and tropical seas, most abundantly in the latter. A few species enter brackish and even fresh water, one having been found as high up the Ganges as the confines of Nepal. However, all spawn in the sea. The variety of species is almost infinite, about 150 being tolerably well known, and many more having been described. The distinction of the species is most difficult, and nearly impossible to those who have no opportunity of closely and long observing them in nature, as they are not only subject to great variation of colour, but also to considerable changes dependent on age. Many are most agreeably coloured, and ornamented with spots, or cross bands or longitudinal stripes; colours which become more uniform with age in those species which attain to a large size. The majority remain of rather small size, growing to a length of one or two feet; but not a few reach more than twice that length, and may even become dangerous to man. Instances of bathers having been attacked by a gigantic species not uncommon at the Seychelles and Aden are on record, the persons having died from the injuries received. Almost all the species are eatable, and many are esteemed as food. One species is common on the British coasts (S. cabrilla), and probably some of the more southern species (S. scriba and S. gigas) occasionally wander as far northwards as the British Channel. The species figured, S. altvelis, is locally distributed over nearly all the tropical parts of the Indian Ocean, and distinguished by particularly high dorsal and anal fins. Anyperodon and Prionodes are two genera closely allied to Serranus.

Plectropoma.—Form of the body and dentition (see p. 127, Fig. [54]) similar to that of Serranus, with a præoperculum serrated behind, and armed with spinous teeth below, which are directed forwards. Dorsal fin with from seven to thirteen spines.

About thirty species from tropical seas are known. Trachypoma is allied to this genus.

Polyprion.—Body oblong, rather compressed, covered with small scales. All the teeth are villiform; teeth on the vomer, palatine bones, and the tongue. One dorsal with eleven or twelve spines; anal with three. Præoperculum denticulated; a strong, rough, longitudinal ridge on the operculum.

Two species are known: one from the European coasts (P. cernium), and one from Juan Fernandez (P. kneri). They attain to a weight of 80 lbs. and more. The European species has the habit of accompanying floating wood, to which they are attracted by the small marine species generally surrounding such objects, and affording a supply of food. It is known by the name of “Stone-bass,” and excellent eating.

Grammistes.—Body rather short, compressed, covered with minute scales imbedded in the thick skin. All the teeth are villiform; teeth on the vomer and palatine bones. Two dorsal fins, the first with seven spines. Præoperculum without serrature, but with three short spines. A short skinny barbel is frequently developed at the chin.

Three species are known from the Indo-Pacific; they are of small size. One, G. orientalis, is black, with six or seven white longitudinal stripes, and one of the most common coast-fishes of that ocean.

Rhypticus.—Body oblong, compressed, covered with minute scales imbedded in the thick skin. All the teeth are villiform; teeth on the vomer and palatine bones. The spines of the vertical fins are but little developed, always in small number and short, and may disappear entirely. Præoperculum not serrated, with some obtuse spines.

Four species are known: three from the West Indies and one from the Galapagoes Islands.

Other genera allied to the two preceding are Aulacocephalus from Mauritius, Reunion, and Japan; and Myriodon from the coasts of Australia.

Diploprion.—Body rather elevated, compressed, with small scales. All the teeth villiform; teeth on the vomer and palatine bones. Two dorsal fins, the first with eight spines; anal with two. Præoperculum with a double denticulated limb.

Fig. 153.—Mesoprion monostigma.

The single species known (D. bifasciatum), is very common in the East Indian Archipelago, and on the coasts of Southern China and Japan. It is of small size, and ornamented with two broad black cross-bands.

Mesoprion.—Body oblong, compressed, covered with scales of moderate size. Teeth villiform, with canines in both jaws; teeth on the vomer and palatine bones. One dorsal fin, with ten or eleven, rarely with more spines; anal fin with three. Præoperculum serrated; in some species (Genyoroge) a more or less distinct spinous knob projects from the surface of the interoperculum, and is received in a more or less deep notch of the præopercular margin.

Fig. 154.—Opercles a, of Mesoprion; b, of Genyoroge; o, knob received in a notch of the præoperculum.

About seventy species are known from tropical seas in both hemispheres, but it is noteworthy that the species with the peculiar protuberance of the interoperculum are confined to the Indo-Pacific. The coloration is much more simple than in the small-scaled Serrani, a uniform hue of greenish, pink, or red prevailing; species with longitudinal bands are scarce, but not rarely dark cross-bands or a large spot on the side occur. The majority of the species remain within very moderate dimensions, specimens exceeding three feet in length being scarce. They are generally eaten, and some of the species belong to the commonest fishes of the tropics, as M. bengalensis, chrysurus, gembra, griseus, and others.

Glaucosoma from Japan and Australia is allied to Mesoprion.

Dules.—Body oblong, compressed, with scales of moderate size, and very indistinctly ctenoid. All the teeth are villiform; teeth on the vomer and palatine bones. One dorsal with ten spines; anal fin with three. Præoperculum serrated. Six branchiostegals only.

About ten species are known, inhabiting fresh waters of the coasts of the Indo-Pacific, and being especially common in the islands of this region, and also in Tropical Australia. Some live also in brackish water. Though of small size they are esteemed as food.

Therapon.—Body oblong, compressed, with scales of moderate size. All the teeth are villiform, those of the vomer and palatine bones being rudimentary, and frequently absent. One dorsal, with a depression in its upper margin, and twelve or thirteen spines; anal fin with three. Præoperculum serrated. Air-bladder with two divisions, an anterior and posterior. Six branchiostegals.

About twenty species are known, the distribution of which nearly coincides with Dules, but as some of the species are more or less marine, the genus is spread over the whole area of the tropical Indo-Pacific. Other species, especially those of Australian rivers, are entirely limited to fresh water. Th. theraps, Th. servus, and Th. cuvieri belong to the most common fishes of that area, extending from the east coast of Africa to Polynesia. They are readily recognised by the blackish longitudinal bands with which the body is ornamented. All the species are of small size. Helotes is closely allied to this genus.

Pristipoma.—Body oblong, compressed, with ctenoid scales of moderate size. Cleft of the mouth horizontal, not very wide, with the jaws nearly equal in length anteriorly; a central pit below the chin; villiform teeth in the jaws without canines; palate toothless. One dorsal, with eleven to fourteen spines; anal with three. Vertical fins not scaly, or with scales along the base only. Præoperculum serrated. Branchiostegals, seven.

Fig. 155.—Lower view of mandible of Pristipoma manadense.

About forty species are known, all from the sea. They are extremely common between the tropics, some of the species extending into the neighbouring sub-tropical parts. They do not attain a large size, and generally have a plain coloration. Conodon is an allied genus.

Fig. 156.—Hæmulon brevirostrum.

Hæmulon.—Body oblong, compressed, with ctenoid scales of moderate size. Cleft of the mouth horizontal, generally wide, with the jaws equal in length anteriorly; a central pit below the chin; villiform teeth in the jaws, without canines; palate toothless. One dorsal, with twelve or thirteen spines; anal with three; the soft portions of the vertical fins scaly to their margins. Præoperculum serrated. Branchiostegals, seven.

Marine; sixteen species are known from the coasts of Tropical America; they are of rather small size. The species figured occurs on both sides of Central America. Hapalogenys is an allied genus.

Diagramma.—Body oblong, compressed, covered with rather small ctenoid scales. Upper profile of the head parabolic; cleft of the mouth small, horizontal; from four to six pores under the mandible, but without central pit. Teeth villiform, without canines; palate toothless. One dorsal fin, with from nine to fourteen spines; anal with three. Vertical fins not scaly. Præoperculum serrated; infraorbital not armed. Branchiostegals, six or seven.

Fig. 157.—Diagramma orientale, from the Indo-Pacific.

Forty species are known, which, with very few exceptions, belong to the tropical parts of the Indo-Pacific. Some attain to a size not very common among Sea-Perches, viz. to a length of from three to four feet. Many are agreeably coloured with black bands or spots. All appear to be esteemed as food. Hyperoglyphe from Australia is allied to this genus.

Lobotes.—Body rather elevated, compressed, with ctenoid scales of moderate size. Eye rather small. Snout obtuse, with oblique cleft of the mouth, and with the lower jaw longest. Teeth villiform, without canines; palate toothless. One dorsal fin with twelve spines; anal with three. Præoperculum denticulated. Branchiostegals, six.

A remarkable fish (L. auctorum) on account of its extraordinary range. Common in many localities, scarcer in others, it occurs in the East Indies, and on all the Atlantic coasts of tropical and temperate America. Döderlein found it on the coast of Sicily in 1875. It lives in salt and brackish water, and is known to attain to a length of two feet.

Histiopterus.—Body rather elevated, strongly compressed, with very small scales. Snout much produced, the anterior profile of the head being concave. Mouth small, at the end of the snout. Teeth villiform, without canines; palate toothless. Some of the spines and rays of the vertical and pectoral fins very long. One dorsal, with about ten spines; anal with three. Præopercular margin partly serrated. Branchiostegals, six.

Marine. Four species are known from Japan and South Australia. The species figured attains to a length of 20 inches, and is esteemed as food. It is known at Melbourne by the names of “Boar Fish” or “Bastard Dorey.”

Fig. 158.—Histiopterus recurvirostris.

Gerres.—Body oblong, or rather elevated, covered with scales of moderate size, which are either entirely smooth or minutely ciliated. Mouth very protractile, and descending when thrust out. Eye rather large. No canine teeth; dentition feeble, and palate toothless. The two divisions of the dorsal fin are nearly separated by a deep incision. Formula of the vertical fins—D. 9/10 A. 2·3/7·9. Caudal fin forked. Præoperculum generally without denticulation. Lower pharyngeal bones coalescent.

Fig. 159.—Gerres altispinis, from the mouth of the Ganges.

More than thirty species are known of this genus, which bear so close a resemblance to one another that their distinction is rather difficult. They live in the seas between the Tropics, and some, perhaps all, of the species enter fresh water. Very rarely they exceed a length of ten inches; nearly all have a plain silvery coloration. The coalescence of their lower pharyngeals renders their systematic position rather uncertain, and, indeed, some Ichthyologists have referred them to the Pharyngognaths.

Scolopsis.—Body oblong, covered with scales finely serrated and of moderate size. Jaws nearly equal in length anteriorly; cleft of the mouth horizontal. Teeth villiform, without canines; palate toothless. One dorsal fin. Formula of the vertical fins: D. 10/9 A. 3/7. Caudal fin forked. Præoperculum distinctly denticulated; infraorbital ring with a spine directed backwards. Branchiostegals, five.

Fig. 160.—Infraorbital spine of Scolopsis monogramma.

Marine, and of small size. Twenty-five species are known from the tropical parts of the Indo-Pacific. Heterognathodon is an allied genus, but without the infraorbital spine.

Dentex.—Body oblong, covered with ctenoid scales of moderate size. Cleft of the mouth nearly horizontal, with the jaws equal in length anteriorly. Canine teeth in both jaws; palate toothless. One dorsal fin. Formula of the vertical fins: D. 10·13/10·12 A. 3/8·9. Caudal fin forked. Præoperculum without serrature; præorbital unarmed and broad, there being a wide space between the eye and the cleft of the mouth. Cheek covered by more than three series of scales. Branchiostegals, six.

Marine Fishes, rather locally distributed in the Mediterranean, on the south coast of Africa, in the Red Sea, East Indian Archipelago, and on the coasts of China and Japan. About fourteen species are known, some of which attain a weight of 30 lbs. and more. They form a not unimportant article of food where they are found in any number, as on the Cape of Good Hope. The species found in the Mediterranean (D. vulgaris) wanders sometimes to the south coast of England, and is one of the larger species. The coloration of these fishes is rather uniform, silvery, or pink, or greenish. Symphorus is an allied genus from the Indo-Pacific.

Synagris.—Body rather elongate, covered with ciliated scales of moderate size. Cleft of the mouth horizontal, with the jaws equal in length anteriorly. One continuous dorsal, with feeble spines; dorsal 10/9, anal 3/7. Caudal deeply forked. Teeth villiform, with canines at least in the upper jaw. Infraorbital not armed; præoperculum without, or with a very indistinct serrature. Cheek with three series of scales. Branchiostegals six.

Marine fishes of small size; about twenty species are known from the tropical parts of the Indo-Pacific. Pentapus, Chætopterus, and Aphareus are allied genera from the same area.

Maena.—Body oblong, compressed, covered with ciliated scales of moderate size. Mouth very protractile, the intermaxillary pedicles extending backwards to the occiput. Teeth villiform; minute teeth on the vomer. One dorsal, scaleless, with feeble spines. D. 11/11, A. 3/9. Caudal fin forked. Præoperculum without serrature. Branchiostegals six.

Small fishes from the Mediterranean, known to the ancients; valueless as food. Three species.

Smaris.—Body oblong or cylindrical, covered with rather small ciliated scales. Mouth very protractile, the intermaxillary pedicles extending backwards to the occiput. Teeth villiform. Palate toothless. One dorsal, scaleless, with eleven or more very feeble spines; anal with three. Caudal fin forked. Præoperculum without serrature. Branchiostegals six.

Small fishes from the Mediterranean. Six species.

Cæsio.—Body oblong, covered with ciliated scales of moderate size. Cleft of the mouth more or less oblique, with the jaws equal in length anteriorly, or with the lower somewhat projecting. Teeth villiform; palate generally toothless. One dorsal, with from nine to thirteen very feeble spines, with the anterior part highest, and the posterior covered with minute scales. Caudal fin deeply forked. Præoperculum without, or with minute, serrature.

Small fishes from the Indo-Pacific. Twelve species.

Erythrichthys.—Body elongate, covered with small ciliated scales. Mouth very protractile, the pedicles of the intermaxillary extending to the occiput. Dentition quite rudimentary or entirely absent Two dorsal fins connected by a series of very feeble spines; also the anterior spines are feeble. Præoperculum not serrated.

Fig. 161.—Erythrichthys nitidus.

Fig. 162.—Enlarged scale.

Fig. 163.—Protractile mouth.

Small fishes from various tropical and temperate seas. Four species: the species figured occurs, but is not common, on the coasts of Western Austria, Tasmania, and New Zealand.

Oligorus.—Body oblong, covered with small scales. Cleft of the mouth rather oblique, the lower jaw being the longer. Teeth villiform, without canines; teeth on the vomer and palatine bones. One dorsal, with eleven spines; anal with three; caudal fin rounded. Præoperculum with a single smooth or obtusely denticulated margin.

To this genus belong two fishes well known on account of the excellent flavour of their flesh. The first (O. macquariensis) is called by the colonists “Murray-Cod,” being plentiful in the Murray River and other rivers of South Australia. It attains to a length of more than three feet, and to a weight of nearly 100 lbs. The second (O. gigas) is found in the sea, on the coast of New Zealand, and called by the Maoris and colonists “Hapuku.” Its average weight is about 45 lbs., but occasionally large specimens of more than a hundredweight are caught. At certain localities it is so plentiful that it may form an important article of trade. Dr. Hector, who has had opportunity of examining it in a fresh state, has pointed out anatomical differences from the Murray-Cod, from which it appears that it would be better placed in a distinct genus.

Fig. 164.—The Murray-Cod, Oligorus macquariensis.

Grystes.—Body oblong, covered with scales of moderate size. All the teeth villiform, without canines; teeth on the vomer and palatine bones. One dorsal fin with ten spines; anal with three; caudal fin rounded. Præoperculum with a single smooth margin.

One species, from the fresh waters of the United States (G. salmonoides), attains to a length of more than two feet. It is known by the name of “Growler,” and eaten.

Arripis.—Body oblong, covered with scales of moderate size. All the teeth villiform, without canines; teeth on the vomer and palatine bones. One dorsal fin, with nine slender spines; anal with three. Præoperculum denticulated.

Fig. 165.—Arripis salar, South Australia.

Three species are known, from the coasts of Southern Australia and New Zealand. They are named by the colonists Salmon or Trout, from their elegant form and lively habits, and from the sport they afford to the angler. Their usual size is from 1 to 3 lbs., but specimens of double that weight are taken. The smaller specimens are the more delicate and better flavoured. When not fresh, they are liable to assume poisonous properties; and cases of poisoning are not unfrequently caused by them.

Huro.—Body oblong, compressed, covered with scales of moderate size. All the teeth villiform; bones of the head without serrature. Mouth rather oblique, with the lower jaw projecting. Two dorsal fins, the first with six spines.

The “Black Bass” of Lake Huron (Huro nigricans).

Ambassis.—Body short, strongly compressed, covered with large thin deciduous scales. Mouth oblique, with the lower jaw longest; teeth villiform, without conspicuously larger canines; teeth on the vomer and palatine bones. Two dorsal fins, the first with seven, the anal with three spines; a horizontal spine pointing forwards in front of the dorsal fin. The lower limb of the præoperculum with a double serrated margin.

This genus comprises the smallest of all Percoids, some of the species not much exceeding one inch in length. They are most abundant on the coasts of the tropical Indo-Pacific, and in the fresh waters belonging to that area. The species are numerous (some thirty having been described), and very difficult to distinguish. Their coloration is very plain, a silvery hue prevailing over the whole fish.

Apogon.—Body rather short, covered with large deciduous scales. Mouth oblique, with the lower jaw longest; teeth villiform, without canines; teeth on the vomer and palatine bones. Two dorsal fins, the first with six or seven, the anal with two spines. Præoperculum with a double edge on the margin, one or both edges being serrated. Seven branchiostegals.

Fig. 166.—Apogon frenatus.

Although of similarly small size, the fishes of this genus represent a more highly developed form of the Percoid type than Ambassis. Their distribution coincides very much with that of Ambassis, but they are chiefly marine, comparatively few of the species entering fresh water. They belong to the kind of fishes which, from their habit, are termed “Coral Fishes,” being found in greatest abundance on, or in the neighbourhood of, coral reefs, in company with Chætodonts, Pomacentridæ, and others. Their colours also are ornamental and highly diversified, as is generally the case in coral fishes, the majority of the species showing transverse or longitudinal bands or large spots, and numerous other smaller markings which, in the dead fish, soon disappear. Nearly one hundred species have been described, of which a few only occur in the Atlantic, one extending northwards into the Mediterranean.

Chilodipterus, Acropoma, and Scombrops are allied genera, but with canine teeth in one or both jaws.

Pomatomus.—Body oblong, covered with scales of moderate size. Eye very large. All the teeth villiform, without canines; teeth on the vomer and palatine bones. Two dorsal fins, the first with seven, the anal with two spines. No serration on any of the bones of the head. Branchiostegals seven.

One species only is known, P. telescopium, which grows to a length of nearly two feet. It is not uncommon in the Mediterranean and neighbouring parts of the Atlantic, but only occasionally caught, as it lives habitually at a greater depth than any other Percoid as far as is known at present, probably at depths from 80 to 200 fathoms; a habit sufficiently indicated by its exceedingly large eye.

Priacanthus.—Body short, compressed, covered with small rough scales, which extend also over the short snout. Lower jaw and chin prominent. Eye large. All the teeth villiform, without canines; teeth on the vomer and palatine bones. One dorsal fin with ten spines, anal with three. Præoperculum serrated, with a more or less prominent, flat, triangular spine at the angle.

A very natural genus, easily recognised, and without direct relation to the other Percoid genera. The species, of which seventeen are known, are spread over nearly all the tropical seas, and belong to the more common fishes. They scarcely exceed a length of twelve inches, and are very uniformly coloured, red, pink, and silvery prevailing.

---

The following three genera form a group by themselves, which, however, is defined rather by its geographical limits and similarity of general appearance than by distinctive anatomical characters. The species are abundant in the fresh waters of the United States, and well known by the name of “Sun Fishes.” They rarely exceed a length of six inches, and are not used as food. The number of species is uncertain.

Centrarchus.—Body short, compressed, with scales of moderate size. All the teeth villiform, without canines; teeth on the vomer, palatines, and on the tongue. One dorsal fin; anal generally with more than three spines. Præoperculum without serrature; operculum not lobed.

Bryttus.—Body short, compressed, with scales of moderate size. All the teeth villiform, without canines; teeth on the vomer and palatine bones. One dorsal fin with nine or ten, anal with three spines. Præoperculum not serrated; operculum with a rounded membranaceous coloured lobe behind.

Pomotis.—Body short, compressed, with scales of moderate length. All the teeth villiform, without canines; teeth on the vomer, but none on the palatine bones. One dorsal, with from nine to eleven spines, anal with three. Præoperculum entire or minutely serrated; operculum with a rounded membranaceous coloured lobe behind.

---

A North American Freshwater genus, Aphredoderus, occupies a perfectly isolated position in the system, and is evidently the type of a distinct family. It resembles the “Sun-fishes” of the same country with regard to the structure of the vertical fins, but has the vent situated in front of the ventrals, which are composed of more than five soft rays. The body is oblong, compressed, covered with ctenoid scales. The dorsal fin is single, and has three spines in front. Infraorbital and præoperculum with spinous teeth. Villiform teeth in the jaws, on the vomer and palatine bones. A. sayanus from the southern streams and fresh waters of the Atlantic States.

To complete the list of Percoid genera, we have to mention the following:—Siniperca, Etelis, Niphon, Aprion, Apsilus, Pentaceros, Velifer, Datnioides, Percilia, Lanioperca.

Second Family—Squamipinnes.

Body compressed and elevated, covered with scales, either finely ctenoid or smooth. Lateral line continuous, not continued over the caudal fin. Mouth in front of the snout, generally small, with lateral cleft. Eye lateral, of moderate size. Six or seven branchiostegals. Teeth villiform or setiform, in bands, without canines or incisors. Dorsal fin consisting of a spinous and soft portion of nearly equal development; anal with three or four spines, similarly developed as the soft dorsal, both being many-rayed. The vertical fins more or less densely covered with small scales. The lower rays of the pectoral fin branched, not enlarged; ventrals thoracic, with one spine and five soft rays. Stomach coecal.

The typical forms of this family are readily recognised by the form of their body, and by a peculiarity from which they derive their name Squamipinnes; the soft, and frequently also the spinous part of their dorsal and anal fins are so thickly covered with scales that the boundary between fins and body is entirely obliterated. The majority are inhabitants of the tropical seas, and abound chiefly in the neighbourhood of coral-reefs. The beauty and singularity of distribution of the colours of some of the genera, as Chætodon, Heniochus, Holacanthus, is scarcely surpassed by any other group of fishes. They remain within small dimensions, and comparatively few are used as food. They are carnivorous, feeding on small invertebrates. Only a few species enter brackish water.

Extinct representatives of this family are not scarce at Monte Bolca and in other tertiary formations. All, at least those admitting of definite determination, belong to existing genera, viz. Holacanthus, Pomacanthus, Ephippium, Scatophagus. Very singular is the occurrence of Toxotes in the Monte Bolca strata.

The following genera have no teeth on the palate:—

Chætodon.—One dorsal fin, without any notch in its upper margin, and with the soft and spinous portions similarly developed; none of the spines elongate. Snout short or of moderate length. Præoperculum without, or with a fine, serration, and without spine at the angle. Scales generally large or of moderate size.

Fig. 167.—Chætodon ephippium.

Seventy species are known from the tropical parts of the Atlantic and Indo-Pacific, nearly all being beautifully ornamented with bands or spots. Of the ornamental markings a dark or bicoloured band, passing through the eye and ascending towards the back, is very generally found in these fishes; it frequently occurs again in other marine Acanthopterygians, in which it is not rarely a sign of the immature condition of the individual. The Chætodonts are most numerous in the neighbourhood of the coral-reefs of the Indo-Pacific, the species figured (C. ephippium) being as common in the East Indian Archipelago as in Polynesia, like many others of its congeners.

Chelmo differs from Chætodon only in having the snout produced into a more or less long tube.

Fig. 168.—Chelmo marginalis, from the coast of Australia.

Only four species are known, locally distributed in the tropical seas. Ch. rostratus, the oldest species known, is said to have the instinct of throwing a drop of water from its bill so as to light upon any insect resting on a leaf, and thus make it fall, that it may instantly dart upon it. This statement is erroneous, and probably rests upon the mistaken notion that the long bill is especially adapted for this manœuvre, which, indeed, is practised by another fish of this family (Toxotes). The long slender bill of Chelmo (which is a true saltwater fish) rather enables it to draw from holes and crevices animals which otherwise could not be reached by it.

Heniochus.—One dorsal, with from eleven to thirteen spines, the fourth of which is more or less elongate and filiform. Snout rather short or of moderate length. Præoperculum without spine. Scales of moderate size.

Four species are known from the tropical Indo-Pacific. H. macrolepidotus is one of the most common fishes of that area; the species figured (H. varius) retains in a conspicuous manner horn-like protuberances on bones of the head, with which the young of all the species of this genus seem to be armed.

Fig. 169.—Heniochus varius.

Holacanthus.—Præoperculum with a strong spine at the angle. One dorsal, with from twelve to fifteen spines. Scales of moderate or small size.

Forty species are known, which, in their geographical distribution accompany, and are quite analogous to, the Chætodonts. One of the most common and most beautiful is called “Emperor of Japan” by the Dutch, which name has been adopted by Bloch for its specific designation, Holacanthus imperator. Its body is blue, longitudinally traversed by about thirty yellow bands; the ocular band, and the side behind the head, are black, edged with yellow; the caudal fin is yellow. It is a large species of this genus, sometimes attaining a length of 15 inches, and as an article of food is one of the most esteemed of all the Indian species. With regard to beauty of colours it is surpassed by another allied species, H. diacanthus, which likewise ranges from the east coast of Africa to Polynesia.

Pomacanthus differs from Holacanthus in having from eight to ten spines only in the dorsal fin.

The single species (P. paru) on which this genus is founded is one of the most common fishes of the West Indies, and offers one of the most remarkable instances of variation of colour within the limits of the same species: some specimens being ornamented with more or less distinct yellowish cross-bands, others with yellow crescent-shaped spots; in others black spots predominate.

Fig. 170.—Scatophagus multifasciatus.

Scatophagus.—Two dorsal fins, united at the base, the first with ten or eleven spines; only the second is scaly. A recumbent spine before the dorsal, pointing forwards. Anal with four spines. Snout rather short. Præoperculum without spine. Scales very small.

Four species are known, from the Indian Ocean, of which S. argus is the most generally known, in fact, one of the most common Indian shore-fishes. It freely enters large rivers, and is said not to be particular in the selection of its food. The species figured (S. multifasciatus) represents S. argus on the coasts of Australia.

Fig. 171.—Bony enlargement of cranial bones of Ephippus. a, Enlargement of the frontal, and b, of the supraoccipital bones; c, interorbital septum; d, basis cranii. ⅓ nat. size.

Ephippus.—Snout short, with the upper profile parabolic. Dorsal fin deeply emarginate between the spinous and soft portions, the former with nine spines, the third of which is rather elongate, and flexible; spinous portion not scaly; anal spines three. Pectoral fin short. Præoperculum without spine. Scales of moderate size, or rather small.

Two or three species are known from the warmer parts of the Atlantic and Indian Oceans. The Atlantic species (E. faber) shows the remarkable peculiarity that in old specimens (12 and more inches long) the occipital crest, and sometimes some of the anterior neural and hæmal spines are enormously enlarged into a globular bony mass. This can hardly be regarded as a pathological change of the bone, as it has been found in all old specimens, without exception.

Drepane is allied to Ephippus, but has very long falciform pectoral fins. The single species D. punctata is common in the Indian Ocean and on the coasts of Australia. Hypsinotus, from Japan, appears to inhabit a greater depth than the other Squamipinnes.

Scorpis and Atypichthys are genera distinguished from the preceding by the presence of vomerine teeth. They belong to the coast-fauna of Australia, New Zealand, and Chili.

Toxotes.—Body short, compressed, covered with scales of moderate size. Snout pointed, with a wide lateral mouth and projecting lower jaw. One dorsal, with five strong spines situated on the posterior part of the back; the soft portion and the anal fin scaly, the latter with three spines. Villiform teeth in the jaws, on the vomer and palatine bones. Scales of moderate size, cycloid.

Fig. 172.—Toxotes jaculator.

Two species are known from the East Indies, one (T. jaculator), which is the more common, ranging to the north coast of Australia. It has received its name from its habit of throwing a drop of water at an insect which it perceives close to the surface, in order to make it fall into it. The Malays, who call it “Ikan sumpit,” keep it in a bowl, in order to witness this singular habit, which it continues even in captivity.

Third Family—Mullidæ.

Body rather low and slightly compressed, covered with large thin scales, without or with an extremely fine serrature. Two long erectile barbels are suspended from the hyoid, and are received between the rami of the lower jaw and opercles. Lateral line continuous. Mouth in front of the snout, with the cleft lateral and rather short; teeth very feeble. Eye lateral, of moderate size. Two short dorsal fins remote from each other, the first with feeble spines; anal similar to the second dorsal. Ventrals with one spine and five rays. Pectorals short. Branchiostegals four; stomach siphonal.

The “Red Mullets” form a very natural family, which, on account of slight modifications of the dentition, has been divided into several sub-genera—Upeneoides, Upeneichthys, Mullus, Mulloides, and Upeneus. They are marine fishes, but many species enter brackish water to feed on the animalcules abounding in the flora of brack-water. About forty different species are known chiefly from tropical seas, the European species (M. barbatus, see p. 43, Fig. [7]), extending far northwards into the temperate zone. None attain to a large size, specimens of from two to three lbs. being not common, but all are highly esteemed as food.

The most celebrated is the European species (of which there is one only, M. surmuletus being probably the female). The ancient Romans called it Mullus, the Greeks τριγλη. The Romans priced it above any other fish; they sought for large specimens far and wide, and paid ruinous prices for them.

“Mullus tibi quatuor emptus

Librarum, cœnæ pompa caputque fuit,

Exclamare libet, non est hic improbe, non est

Piscis: homo est; hominem, Calliodore, voras.”

Martial, x. 31.

Then, as nowadays, it was considered essential for the enjoyment of this delicacy that the fish should exhibit the red colour of its integuments. The Romans brought it, for that purpose, living into the banqueting room, and allowed it to die in the hands of the guests, the red colour appearing in all its brilliancy during the death struggle of the fish. The fishermen of our times attain the same object by scaling the fish immediately after its capture, thus causing a permanent contraction of the chromatophors containing the red pigment (see p. 183).

Fourth Family—Sparidæ.

Body compressed, oblong, covered with scales, the serrature of which is very minute, and sometimes altogether absent. Mouth in front of the snout, with the cleft lateral. Eye lateral, of moderate size. Either cutting teeth in front of the jaws, or molar teeth on the side; palate generally toothless. One dorsal fin, formed by a spinous and soft portion of nearly equal development. Anal fin with three spines. The lower rays of the pectoral fin are generally branched, but in one genus simple. Ventrals thoracic, with one spine and five rays.

The “Sea-breams” are recognised chiefly by their dentition, which is more specialised than in the preceding families, and by which the groups, into which this family has been divided, are characterised. They are inhabitants of the shores of all the tropical and temperate seas. Their coloration is very plain. They do not attain to a large size, but the majority are used as food.

The extinct forms found hitherto are rather numerous; the oldest come from the cretaceous formation of Mount Lebanon; some belong to living genera, as Sargus, Pagellus; of others from Eocene and Miocene formations no living representative is known—Sparnodus, Sargodon, Capitodus, Soricidens, Asima.

First Group—Cantharina.—More or less broad cutting, sometimes lobate, teeth in front of the jaws; no molars or vomerine teeth; the lower pectoral rays are branched. Partly herbivorous, partly carnivorous. The genera belonging to this group are:—Cantharus from the European and South African coasts, of which one species (C. lineatus), is common on the coasts of Great Britain, and locally known by the names “Old Wife,” “Black Sea-bream;” Box, Scatharus, and Oblata from the Mediterranean and neighbouring parts of the Atlantic; Crenidens and Tripterodon from the Indian Ocean; Pachymetopon, Dipterodon, and Gymnocrotaphus from the Cape of Good Hope; Girella and Tephræops from Chinese, Japanese, and Australian Seas; Doydixodon from the Galapagos Islands and the coasts of Peru.

Fig. 173.—Tephræops richardsonii, from King George’s Sound.

Second Group—Haplodactylina.—In both jaws flat and generally tricuspid teeth; no molars; vomerine teeth. The lower pectoral rays simple, not branched. Vegetable feeders. Only one genus is known, Haplodactylus, from the temperate zone of the Southern Pacific.

Third Group—Sargina.—Jaws with a single series of incisors in front, and with several series of rounded molars on the side. One genus is known, Sargus, which comprises twenty species; several of them occur in the Mediterranean and the neighbouring parts of the Atlantic, and are popularly called “Sargo,” “Sar,” “Saragu:” names derived from the word Sargus, by which name these fishes were well known to the ancient Greeks and Romans. One of the largest species is the “Sheep’s-head” (Sargus ovis), from the coasts of the United States, which attains to a weight of 15 lbs., and is highly esteemed on account of the excellency of its flesh. Singularly enough, this genus occurs also on the east coast of Africa, one of these East-African species being identical with S. noct from the Mediterranean. These fishes evidently feed on hard-shelled animals, which they crush with their molar teeth.

Fig. 174.—The Sheep’s-head, Sargus ovis, of North America.

Fig. 175.—Scale of Lethrinus.

Fourth Group—Pagrina.—Jaws with conical teeth in front and molar teeth on the sides. Feeding, as the preceding, on hard-shelled animals, like Mollusks and Crustaceans. This group is composed of several genera:—

Lethrinus.—Cheeks scaleless. Body oblong, covered with scales of moderate size (L. lat. 45–50). Canine teeth in front; lateral teeth in a single series, broadly conical or molar-like. Formula of the fins: D. 10/9, A. 3/8.

More than twenty species are known, all of which, with one exception, occur in the tropical Indo-Pacific. The species, forming this exception, occurs, singularly enough, on the west coast of Africa, where more than one Indian genus reappears in isolated representative species. Some Lethrini attain to a length of three feet.

Sphærodon is closely allied to Lethrinus, but has scales on the cheek. One species from the Indo-Pacific.

Pagrus.—Body oblong, compressed, with scales of moderate size. Several pairs of strong canine-like teeth in both jaws; molars arranged in two series. Cheeks scaly. The spines of the dorsal fin, eleven or twelve in number, are sometimes elongate, and can be received in a groove; anal spines three.

Thirteen species are known, chiefly distributed in the warmer parts of the temperate zones, and more scantily represented between the tropics. Several species (P. vulgaris, P. auriga, P. bocagii) occur in the Mediterranean and the neighbouring parts of the Atlantic; one (P. argyrops) is well known on the coasts of the United States under the names of “Scup,” “Porgy,” or “Mishcup,” and one of the most important food fishes, growing to a length of 18 inches and a weight of 4 lbs.; another (P. unicolor) is one of the best-known sea-fishes of Southern Australia and New Zealand, where it is called “Snapper;” it is considered very good eating, like all the other species of this genus, and attains, like some of them, a length of more than 3 feet and a weight exceeding 20 lbs.

Pagellus.—Body oblong, compressed, with scales of moderate size. Jaws without canines; molars on the sides arranged in several series. Cheeks scaly. The spines of the dorsal fin, from eleven to thirteen in number, can be received in a groove; anal spines three.

Seven species are known, the majority of which are European, as P. erythrinus, common in the Mediterranean, and not rare on the south coast of England, where it is generally termed “Becker;” P. centrodontus, the common “Sea-bream” of the English coasts, distinguished by a black spot on the origin of the lateral line; in the young, which are called “Chad” by Cornish and Devon fishermen, this spot is absent; P. owenii, the “Axillary or Spanish Sea-Bream,” likewise from the British coasts. Pagellus lithognathus, from the coasts of the Cape of Good Hope, attains to a length of four feet, and is one of the fishes which are dried for export and sale to whalers.

Chrysophrys.—Body oblong, compressed, with scales of moderate size. Jaws with four or six canine teeth in front, and with three or more series of rounded molars on each side. Cheeks scaly. The spines of the dorsal fin, eleven or twelve in number, can be received in a groove; anal spines three.

Some twenty species are known from tropical seas and the warmer parts of the temperate zones. Generally known is Ch. aurata, from the Mediterranean, occasionally found on the south coast of England, where it is named “Gilthead.” The French call it “Daurade,” no doubt from the Latin Aurata, a term applied to it by ancient authors. The Greeks named it Chrysophrys (i.e. golden eyebrow), in allusion to the brilliant spot of gold which it bears between its eyes. According to Columella, the Aurata was among the number of the fishes brought up by the Romans in their vivaria; and the inventor of those vivaria, one Sergius Orata, is supposed to have derived his surname from this fish. It is said to grow extremely fat in artificial ponds. Duhamel states that it stirs up the sand with the tail, so as to discover the shell-fish concealed in it. It is extremely fond of mussels, and its near presence is sometimes ascertained by the noise which it makes while breaking their shells with its teeth. Several species found on the Cape of Good Hope attain to as large a size as Pagellus lithognathus, and are preserved for sale like that species. Chrysophrys hasta is one of the most common species of the East Indian and Chinese coasts, and enters large rivers.

Fifth Group—Pimelepterina.—In both jaws a single anterior series of cutting teeth, implanted by a horizontal posterior process, behind which is a band of villiform teeth. Villiform teeth on the vomer, palatines and the tongue. Vertical fins densely covered with minute scales. Only one genus is known, Pimelepterus, with six species from tropical seas. These fishes are sometimes found at a great distance from the land.

Fifth Family—Hoplognathidæ.

Body compressed and elevated, covered with very small ctenoid scales. Lateral line continuous. The bones of the jaws have a sharp dentigerous edge, as in Scarus. The teeth, if at all conspicuous, being continuous with the bone, forming a more or less indistinct serrature; no teeth on the palate. The spinous portion of the dorsal fin is rather more developed than the soft; the spines strong; anal with three spines, similar to the soft dorsal. Ventrals thoracic, with one spine and five soft rays.

One genus only is known, Hoplognathus, with four species from Australian, Japanese, and Peruvian coasts.

Fig. 176.—Teeth of Hoplognathus.

Sixth Family—Cirrhitidæ.

Body oblong, compressed, covered with cycloid scales; lateral line continuous. Mouth in front of the snout, with lateral cleft. Eye lateral, of moderate size. Cheeks without a bony stay for the præoperculum. Generally six, sometimes five or three branchiostegals. Dentition more or less complete, composed of small pointed teeth, sometimes with the addition of canines. One dorsal fin, formed by a spinous and soft portion, of nearly equal development. Anal with three spines, generally less developed than the soft dorsal. The lower rays of the pectoral fins simple and generally enlarged; ventrals thoracic, but remote from the root of the pectorals, with one spine and five rays.

The fishes of this family may be readily recognised by their thickened, undivided lower pectoral rays, which in some are evidently auxiliary organs of locomotion, in others, probably, organs of touch. They differ from the following family, the Scorpænidæ, in lacking the bony connection between the infraorbital ring and the præoperculum. Two groups may be distinguished in this family, which, however, are connected by an intermediate genus (Chironemus). The first, distinguished by the presence of vomerine teeth, consists of Cirrhites and Chorinemus, small prettily coloured fishes. The former genus is peculiar to the Indo-Pacific, and consists of sixteen species; the second, with three species, seems to be confined to the coasts of Australia and New Zealand. The second group lacks the vomerine teeth, and comprises the following genera:—

Chilodactylus.—One dorsal fin, with from sixteen to nineteen spines; anal fin of moderate length; caudal forked. One of the simple pectoral rays more or less prolonged, and projecting beyond the margin of the fin. Teeth in villiform bands; no canines. Præoperculum not serrated. Scales of moderate size. Air-bladder with many lobes.

Fig. 177.—Chilodactylus macropterus, from Australia.

Seventeen species are known, chiefly from the temperate parts of the Southern Pacific, and also from the coasts of Japan and China. They belong to the most valuable food-fishes, as they grow to a considerable size (from five to twenty-five lbs.), and are easily caught in numbers. At the Cape of Good Hope they are very abundant, and preserved in large quantities for export.

Mendosoma from the coast of Chili, and Nemadactylus from Tasmania, are allied genera.

Latris.—Dorsal fin deeply notched; the spinous portion with seventeen spines; anal fin many-rayed. None of the simple pectoral rays passes the margin of the fin. Teeth villiform; no canines. Præoperculum minutely serrated. Scales small.

Two species only are known from Tasmania and New Zealand, which belong to the most important food-fishes of the Southern Hemisphere. Latris hecateia or the “Trumpeter,” ranges from sixty to thirty lbs. in weight, and is considered by the colonists the best flavoured of any of the fishes of South Australia, Tasmania, and New Zealand, and consumed smoked as well as fresh. The second species, Latris ciliaris, is smaller, scarcely attaining a weight of twenty lbs., but more abundant; it is confined to the coast of New Zealand.

Fig. 178.—Skull of Scorpæna percoides; so, Suborbital ring; pr, Præoperculum; st, Bony stay, connecting the sub-orbital with the præoperculum.

Seventh Family—Scorpænidæ.

Body oblong, more or less compressed, covered with ordinary scales, or naked. Cleft of the mouth lateral or subvertical. Dentition feeble, consisting of villiform teeth; and generally without canines. Some bones of the head armed, especially the angle of the præoperculum, its armature receiving additional support by a bony stay, connecting it with the infraorbital ring. The spinous portion of the dorsal fin equally or more developed than the soft and than the anal. Ventrals thoracic, generally with one spine and five soft rays, sometimes rudimentary.

This family consists of carnivorous marine fishes only; some resemble the Sea-Perches in form and habits, as Sebastes, Scorpæna, etc., whilst others live at the bottom of the sea, and possess in various degrees of development those skinny appendages resembling the fronds of seaweeds, by which they either attract other fishes, or by which they are enabled more effectually to hide themselves. Species provided with those appendages have generally a coloration resembling that of their surroundings, and varying with the change of locality. The habit of living on the bottom has also developed in many Scorpænoids separate pectoral rays, by means of which they move or feel. Some of the genera live at a considerable depth, but apparently not beyond 300 fathoms. Nearly all are distinguished by a powerful armature either of the head, or fin spines, or both; and in some the spines have been developed into poison organs.

The only fossil representative known at present is a species of Scorpæna from the Eocene of Oran.

Sebastes.—Head and body compressed; crown of the head scaly to, or even beyond, the orbits; no transverse groove on the occiput. Body covered with scales of moderate or small size, and without skinny tentacles. Fin-rays not elongate; one dorsal, divided by a notch into a spinous and soft portion, with twelve or thirteen spines; the anal with three. No pectoral appendages. Villiform teeth in the jaws, on the vomer, and generally on the palatine bones. Vertebræ more than twenty-four.

About twenty species are known, principally from seas of the temperate zones, as from the coasts of Northern Europe (S. norvegicus, S. viviparus), of Japan, California, New Zealand, and Van Diemen’s Land. All seem to prefer deep water to the surface, and Sebastes macrochir has been obtained at a depth of 345 fathoms. In their general form they resemble the Sea-Perches, attain to a weight of from one to four lbs., and are generally esteemed as food.

Scorpæna.—Head large, slightly compressed, generally with a transverse naked depression on the occiput; bones of the head armed with spines, and generally with skinny tentacles. Scales of moderate size. Mouth large, oblique. Villiform teeth in the jaws, and at least on the vomer. One dorsal, 12–13/9, A. 3/5. Pectoral fins without detached rays, large, rounded, with the lower rays simple and thickened. Air-bladder none. Vertebræ twenty-four.

Fig. 179.—Head of Scorpæna percoides, from New Zealand.

Fig. 180.—Scorpæna bynoensis, from the coasts of Australia.

About forty species are known from tropical and sub-tropical seas. They lead a sedentary life, lying hidden in the sand, or between rocks covered with seaweed, watching for their prey, which chiefly consists of small fishes. Their strong undivided pectoral rays aid them in burrowing in the sand, and in moving along the bottom. The type of their coloration is very much the same in all the species, viz. an irregular mottling of red, yellow, brown, and black colours, but the distribution of these colours varies exceedingly, not only in the same species but also in the same individuals. They do not attain to any considerable size, probably never exceeding a length of 18 inches. Their flesh is well flavoured. Wounds inflicted by their fin-spines are exceedingly painful, but not followed by serious consequences.

Glyptauchen and Lioscorpius are genera closely allied to Scorpæna, from Australian seas.

Setarches is also allied to the preceding genera, and provided with very large eyes, in accordance with the depth (215 fathoms) which the two species known at present inhabit; one has been found near Madeira, the other near the Fiji Islands.

Pterois.—Head and body compressed; scales of small or moderate size. Bones of the head armed with numerous spinous projections, between which often skinny tentacles are developed. The dorsal spines and pectoral rays are more or less prolonged, passing beyond the margin of the connecting membrane. Twelve or thirteen dorsal spines. Villiform teeth in the jaws and on the vomer.

Nine species are known from the tropical Indo-Pacific. They belong to the most singularly formed and most beautifully coloured fishes of the Tropics, and formerly were believed to be able to fly, like Dactylopterus. But the membrane connecting their pectoral rays is much too short and feeble to enable them to raise themselves from the surface of the water.

Apistus.—Head and body compressed, covered with ctenoid scales of rather small size. Some bones of the head, and especially the præorbital, are armed with spines. One dorsal with fifteen spines; the anal with three. The pectoral fin is elongate, and one ray is completely detached from the fin. Villiform teeth in the jaws, on the vomer, and palatine bones. Air-bladder present. A cleft behind the fourth gill.

Two species from the Indian Ocean. These fishes are very small, but of interest on account of the prolongation of their pectoral fins, which indicates that they can take long flying leaps out of the water. However, this requires confirmation by actual observation.

Agriopus.—Head and body compressed, scaleless; head without any, or with very feeble, armature. Cleft of the mouth small, at the end of the produced snout. One dorsal fin, which commences from the head, the spinous portion being formed by from seventeen to twenty-one strong spines; anal short. Villiform teeth in the jaws, generally none on the vomer.

Seven species. This singular genus is peculiar to the temperate parts of the South Pacific, occurring at the Cape, on the coast of South Australia, and Chili. The largest species (A. torvus) attains a length of two and a half feet. Nothing is known of its mode of life.

Synanceia.—General appearance of the fish, especially of the head, monstrous. Scales none; skin with numerous soft warty protuberances or filaments. Mouth directed upwards, wide. Eyes small. From thirteen to sixteen dorsal spines; pectoral fins very large. Villiform teeth in the jaws, and sometimes on the vomer.

Four species are known from the Indo-Pacific, of which S. horrida and S. verrucosa are the most generally distributed, and, unfortunately, the most common. They are justly feared on account of the great danger accompanying wounds which they inflict with their poisoned dorsal spines, as has been already noticed above, p. 191. The greatest length to which they attain does not seem to exceed eighteen inches. They are very voracious fishes, and their stomach is of so great a capacity that they are able to swallow fishes one-third of their own bulk.

Micropus.—Head and body strongly compressed, short, and deep; no scales, but the skin is covered with minute tubercles. Snout very short, with nearly vertical anterior profile. Præorbital, præ- and inter-operculum with spines on the edge. Dorsal fin with seven or eight, anal with two spines. Pectorals short, ventrals rudimentary. Jaws with villiform teeth.

These fishes belong to the smallest of Acanthopterygians, scarcely exceeding 1½ inches in length. Two species are known, which are rather common on the coral reefs of the Pacific.

Chorismodactylus.—Head and body rather compressed, scaleless, with skinny flaps. Bones of the head with prominent ridges; the præorbital, præoperculum, and operculum armed; a depression on the occiput. One dorsal fin, with thirteen spines; the anal with two. Three free pectoral appendages. Ventral fins with one spine and five rays. Villiform teeth in the jaws only.

Only one small species, Ch. multibarbis, is known, from the coasts of India and China.

Fig. 181.—Chorismodactylus multibarbis.

To complete the list of Scorpænoid genera, we have to mention Tænianotus, Centropogon, Pentaroge, Tetraroge, Prosopodasys, Aploactis, Trichopleura, Hemitripterus, Minous and Pelor.

Eighth Family—Nandidæ.

Body oblong, compressed, covered with scales. Lateral line interrupted. Dorsal fin formed by a spinous and soft portion, the number of spines and rays being nearly equal; anal fin with three spines, and with the soft portion similar to the soft dorsal. Ventral fins thoracic, with one spine, and five or four rays. Dentition more or less complete, but feeble.

This small family consists of two very distinct groups.

A. Plesiopina. Marine fishes of small size, with pseudobranchiæ and only four ventral rays. Plesiops from the coral-reefs of the Indo-Pacific, and Trachinops from the coast of New South Wales, belong to this group.

B. Nandina. Freshwater fishes of small size from the East Indies, without pseudobranchiæ, and five ventral rays. The genera are Badis, Nandus, and Catopra.

Ninth Family—Polycentridæ.

Body compressed, deep, scaly. Lateral line none. Dorsal and anal fins long, both with numerous spines, the spinous portion being the more developed. Ventrals thoracic, with one spine and five soft rays. Teeth feeble. Pseudobranchiæ hidden.

Only two genera, each represented by one or two species in the Atlantic rivers of Tropical America, Polycentrus and Monocirrhus, belong to this family. They are small insectivorous fishes.

Tenth Family—Teuthididæ.

Body oblong, strongly compressed, covered with very small scales. Lateral line continuous. Eye lateral, of moderate size. A single series of cutting incisors in each jaw; palate toothless. One dorsal fin, the spinous portion being the more developed; anal with seven spines. Ventral fins thoracic, with an outer and an inner spine, and with three soft rays between.

This family consists of one very natural genus, Teuthis, readily recognised by the singular structure of the fins. In all the species the fin-formula is D. 13/10. A. 7/9. The incisors are small, narrow, and provided with a serrated edge. The air-bladder is large, and forked anteriorly as well as posteriorly. Their skeleton shows several peculiarities: the number of vertebræ is twenty-three, ten of which belong to the abdominal portion. The abdominal cavity is surrounded by a complete ring of bones, the second piece of the coracoid being exceedingly long, and extending along the whole length of the abdomen, where it is joined to a spinous process of the first interhæmal. The pubic bones are slender, long, firmly attached to each other, without leaving a free space between them. They are fastened by a long process which passes the symphysis of the radii, and extends on to that of the humeri.

Fig. 182.—Teuthis nebulosa, Indian Ocean.

Thirty species are known, all from the Indo-Pacific; but they do not extend eastwards beyond 140° long., or to the Sandwich Islands. They are herbivorous, and do not exceed a length of fifteen inches.

Second Division—Acanthopterygii Beryciformes.

Body compressed, oblong, or elevated; head with large muciferous cavities which are covered with a thin skin. Ventral fins thoracic, with one spine and more than five soft rays (in Monocentris with two only).

One family only belongs to this division.

Family—Berycidæ.

Body short, with ctenoid scales, which are rarely absent. Eyes lateral, large (except Melamphaës). Cleft of the mouth lateral, oblique; jaws with villiform teeth; palate generally toothed. Opercular bones more or less armed. Eight (four) branchiostegals.

This family offers several points of biological interest. All its members are strictly marine; but only two of the genera are surface-forms (Holocentrum and Myripristis). All the others descend considerably below the surface, and even some of the species of Myripristis habitually inhabit depths of from 50 to 100 fathoms. Polymixia and Beryx have been found in 345 fathoms. Melamphaës must live at a still greater depth, as we may infer from the small size of its eye; this fish is not likely to come nearer to the surface than to about 200 fathoms. The other genera named have extremely large eyes, and, therefore, may be assumed to ascend into such superficial strata as are still lit up by a certain proportion of sun-rays. The highly-developed apparatus for the secretion of superficial mucus, with which these fishes are provided, is another sign of their living at a greater depth than any of the preceding families of Acanthopterygians. In accordance with this vertical distribution, Berycoid fishes have a wide horizontal range, and several species occur at Madeira as well as in Japan.

Fossil Berycoids show a still greater diversity of form than living; they belong to the oldest Teleosteous fishes, the majority of the Acanthopterygians found in the chalk being representatives of this family. Beryx has been found in several species, with other genera now extinct: Pseudoberyx, with abdominal ventrals, from Mount Lebanon; Berycopsis, with cycloid scales; Homonotus, Stenostoma, Sphenocephalus, Acanus, Hoplopteryx, Platycornus, with granular scales; Podocys, with a dorsal fin extending to the neck; Acrogaster, Macrolepis, and Rhacolepis, from the chalk of Brazil. Species of Holocentrum and Myripristis occur in the Monte Bolca formation.

Monocentris.—Snout obtuse, convex, short; eye of moderate size. Villiform teeth on the palatine bones, but none on the vomer. Opercular bones without armature. Scales very large, bony, forming a rigid carapace. Ventrals reduced to a single strong spine and a few rudimentary rays.

Fig. 183.—Monocentris japonicus.

One species only is known (M. japonicus) from the seas off Japan and Mauritius. It does not attain to any size, and is not common.

Hoplostethus.—Snout very short and obtuse; eye large. Villiform teeth on the palatine bones, but none on the vomer. Operculum unarmed, a strong spine at the scapulary and the angle of the præoperculum. Scales ctenoid, of moderate size; abdominal edge serrated. One dorsal, with six spines; ventrals with six soft rays; caudal deeply forked.

One species only is known (H. mediterraneus), which occurs in the Mediterranean, the neighbouring parts of the Atlantic, and in the sea off Japan.

Trachichthys.—Snout very short and obtuse, with prominent chin; eye large. Villiform teeth on the palatine bones and on the vomer. A strong spine at the scapulary and at the angle of the præoperculum. Scales rather small; abdomen serrated. One dorsal, with from three to six spines; ventral with six soft rays. Caudal forked.

Four species are known from New Zealand and Madeira.

Anoplogaster is an allied genus from tropical parts of the Atlantic; it is scaleless.

Beryx.—Snout short, with oblique cleft of the mouth and prominent chin; eye large. Villiform teeth on the palatine bones and vomer. Opercular bones serrated; no spine at the angle of the præoperculum. Scales ctenoid, of moderate or large size. One dorsal, with several spines; ventrals with seven or more soft rays. Anal with four spines; caudal forked.

Fig. 184.—Beryx decadactylus.

Five species are known from Madeira, the tropical Atlantic, and the seas of Japan and Australia. The species figured is B. decadactylus, common at Madeira, and occurring near Japan at a depth of 345 fathoms; it attains a length of 1½ feet.

Melamphaes.—Head large and thick, with very thin bones, nearly all the superficial bones being transformed into wide muciferous channels. Eye small. Palate toothless; no barbels; opercles not armed. Scales large, cycloid. One dorsal, with six spines; anal spines very feeble; caudal forked. Ventrals with seven rays.

Two species, deep-sea fishes of the Atlantic; they are very scarce, as only three or four specimens have been found hitherto.

Polymixia.—Snout short, with the cleft of the mouth nearly horizontal; eye large. Two barbels at the throat. Opercles without armature. Scales of moderate size. One dorsal. Anal with three or four spines; caudal forked; ventrals with six or seven soft rays.

Three species are known: P. nobilis from Madeira and St. Helena, P. lowei from Cuba, and P. japonica from Japan; the latter species from a depth of 345 fathoms. Average size eighteen inches.

Myripristis.—Snout short, with oblique cleft of the mouth and prominent chin; eye large or very large. Villiform teeth on the vomer and palatine bones. Opercular bones serrated; præoperculum without spine. Scales large, ctenoid. Two dorsals, the first with ten or eleven spines; anal with four spines; caudal forked; ventrals with seven soft rays. Air-bladder divided by a contraction in two parts, the anterior of which is connected with the organ of hearing.

Eighteen species from the tropical seas of both hemispheres, the majority living near the coast at the surface. The coloration is (principally) red or pink on the back and silvery on the sides. They attain a length of about 15 inches, and are esteemed as food.

Holocentrum.—Snout somewhat projecting, with the cleft of the mouth nearly horizontal; eye large. Villiform teeth on the vomer and palatine bones. Opercular bones and præorbital serrated; operculum with two spines behind; a large spine at the angle of the præoperculum. Scales ctenoid, of moderate size. Two dorsals, the first with twelve spines; anal with four spines, the third being very long and strong; caudal forked. Ventrals with seven soft rays.

Fig. 185.—Holocentrum unipunctatum, from the South Sea.

About thirty species are known from the tropical seas of both hemispheres; all are surface fishes, and very common. The young have the upper part of the snout pointed and elongate, and were described as a distinct genus (Rhynchichthys). The coloration of the adult is uniform; red, pink, and silvery prevailing. They attain to a length of about 15 inches, and are esteemed as food.

Third Division—Acanthopterygii Kurtiformes.

One dorsal fin only, much shorter than the anal, which is long and many-rayed. No superbranchial organ.

One family only belongs to this division.

Family—Kurtidæ.

Body compressed, oblong, deep in front, attenuated behind. Snout short. The spines of the short dorsal are few in number, if developed. Scales small or of moderate size. Villiform teeth in the jaws, on the vomer, and palatine bones.

This family consists of a small number of species only, which form two distinct genera, Pempheris and Kurtus. They are shore fishes of tropical seas. In both the air-bladder shows some peculiarity: in Pempheris it is divided into an anterior and posterior portion; in Kurtus it is lodged within the ribs, which are dilated, convex, forming rings. The number of vertebræ is respectively twenty-four and twenty-three.

Fourth Division—Acanthopterygii Polynemiformes.

Two rather short dorsal fins, somewhat remote from each other; free filaments at the humeral arch, below the pectoral fins; muciferous canals of the head well developed.

One family only belongs to this division.

Family—Polynemidæ.

Body oblong, rather compressed, covered with smooth or very feebly ciliated scales. Lateral line continuous. Snout projecting beyond the mouth, which is inferior, with lateral cleft. Eye lateral, large. Villiform teeth in the jaws and on the palate. Ventrals thoracic, with one spine and five rays.

The fishes of this natural family have been divided, on slight differences, into three genera—Polynemus, Pentanemus, and Galeoides. They are found in rather numerous species on the coasts between the tropics, and the majority enter brackish or even fresh water. Very characteristic are the free filaments which in this family are organs of touch; they are inserted on the humeral arch at some distance from the pectoral fin; but, nevertheless, can be regarded only as a detached portion of that fin; they can be moved quite independently of the fin; their number varies from three to fourteen, according to the species; in some they are exceedingly elongate, twice as long as the fish, in others they are not longer or even shorter than the pectoral. It is evident from the whole organisation of these fishes that they live on muddy bottom or in thick water, such as is found near the mouths of great rivers. Their eyes are large, but generally obscured by a filmy skin, so that those feelers must be of great use to them in finding their way and their food. The Polynemoids are very useful to man: their flesh is esteemed, and some of the species are provided with an air-bladder which yields a good sort of isinglass, and forms an article of trade in the East Indies. Some of these fishes attain to a length of four feet.

Fig. 186.—Pentanemus quinquarius, from the West Coast of Africa and the West Indies.

Fifth Division—Acanthopterygii Sciæniformes.

The soft dorsal is more, generally much more, developed than the spinous, and than the anal. No pectoral filaments; head with the muciferous canals well developed.

Also this division is composed of one family only.

Family—Sciænidæ.

Body rather elongate, compressed, covered with ctenoid scales. Lateral line continuous, and frequently extending over the caudal fin. Mouth in front of the snout. Eye lateral, of moderate size. Teeth in villiform bands, sometimes with the addition of canines; no molars or incisor-like teeth in the jaws; palate toothless. Præoperculum unarmed, and without bony stay. Ventrals thoracic, with one spine and five soft rays. Bones of the head with wide muciferous channels. Stomach coecal. Air-bladder frequently with numerous appendages (see pp. 144 and seq.)

The fishes of the “Meagre” family are chiefly coast-fishes of the tropical and sub-tropical Atlantic and Indian Oceans, preferring the neighbourhood of the mouths of large rivers, into which they freely enter, some of the species having become so completely naturalised in fresh water that they are never found nowadays in the sea. Some of the larger species wander far from their original home, and are not rarely found at distant localities as occasional visitors. In the Pacific and on the coast of Australia, where but a few large rivers enter the ocean, they are extremely rare and, in the Red Sea, they are absent. Many attain a large size, and almost all are eaten.

No fossil species have been as yet discovered.

Pogonias.—Snout convex, with the upper jaw overlapping the lower. Mandible with numerous small barbels. No canines. The first dorsal with ten stout spines. Two anal spines, the second very strong. Scales of moderate size.

To this fish (P. chromis) more especially is given the name of “Drum,” from the extraordinary sounds which are produced by it and other allied Sciænoids. These sounds are better expressed by the word drumming than by any other, and are frequently noticed by persons in vessels lying at anchor on the coasts of the United States, where those fishes abound. It is still a matter of uncertainty by what means the “Drum” produces the sounds. Some naturalists believe that it is caused by the clapping together of the pharyngeal teeth, which are very large molar teeth. However, if it be true that the sounds are accompanied by a tremulous motion of the vessel, it seems more probable that they are produced by the fishes beating their tails against the bottom of the vessel in order to get rid of the parasites with which that part of their body is infested. The “Drum” attains to a length of more than four feet, and to a weight exceeding a hundred lbs. Its air-bladder has been figured on p. 146.

Micropogon is closely allied to Pogonias, but has conical pharyngeal teeth. Two species from the western parts of the Atlantic.

Fig. 187.—Pharyngeal bones and teeth of Pogonias chromis. A, Upper; B, Lower pharyngeals.

Umbrina.—Snout convex, with the upper jaw overlapping the lower; a short barbel under the symphysis of the mandible. The first dorsal with nine or ten flexible spines, the anal with one or two. Scales of moderate size.

Fig. 188.—Umbrina nasus, from Panama.

Twenty species are known from the Mediterranean, Atlantic, and Indian Ocean. One well known to the ancients, under the name of Umbra, is the Umbrina cirrhosa of the Mediterranean, the “Umbrine” or “Ombre” of the French, and the “Corvo” of the Italians. It ranges to the Cape of Good Hope, and attains a length of three feet. Also on the coasts of the United States several species occur, as U. alburna, U. nebulosa, etc.

Fig. 189.—Umbrina nasus, from Panama.

Sciæna (including Corvina).—The upper jaw overlapping the lower, or both jaws equal in front. Interorbital space moderately broad and slightly convex. Cleft of the mouth horizontal or slightly oblique. The outer series of teeth is generally composed of teeth larger than the rest, but there are no canines. Eye of moderate size, barbel none.

Fig. 190.—Sciæna richardsonii.

Some fifty species are known, but their distinctive characters have been but imperfectly pointed out. They are found in all the seas and rivers in which Sciænoids generally occur, and many are entirely confined to fresh water, for instance the species figured, Sciæna richardsonii, from Lake Huron; Sc. amazonica; Sc. obliqua, ocellata, oscula, etc., from fresh waters of the United States. Sciæna diacanthus and Sc. coitor belong to the most common fishes of the coasts of the East Indies, ascending the great rivers for a long distance from the sea. One of the European species, Sciæna aquila, has an extremely wide range; it not rarely reaches the British coasts, where it is known as “Meagre,” and has been found at the Cape of Good Hope and on the coast of southern Australia. Like some of the other species it attains to a length of six feet, but the majority of the species of this genus remain within smaller dimensions. A part of the species have the second anal ray very strong, and have been placed into a distinct genus, Corvina,—thus, among others, Sc. nigra from the Mediterranean, and Sc. richardsonii.

Pachyurus is closely allied to Sciæna, but has the vertical fins densely covered with small scales.

Otolithus.—Snout obtuse or somewhat pointed, with the lower jaw longer. The first dorsal with nine or ten feeble spines. Canine teeth more or less distinct. Præoperculum denticulated. Scales of moderate or small size.

About twenty species are known from the tropical and sub-tropical parts of the Atlantic and Indian Oceans. The air-bladder is figured on p. 144.

Ancylodon differs from Otolithus in having very long arrow-shaped or lanceolate canine teeth. Coasts of tropical America.

Collichthys.—Body elongate; head very broad, with the upper surface very convex; cleft of the mouth wide and oblique; no large canines. Eye small. No barbel. Scales small, or of moderate size. The second dorsal very long, caudal pointed.

Three species from the East Indian and Chinese coasts. The great development of the muciferous system on the head and the small eye leads one to suppose that these fishes live in muddy water near the mouths of large rivers. The air-bladder has been described on p. 144.

Other genera belonging to this family are Larimus, Eques, Nebris, and Lonchurus.

Fig. 191.—Histiophorus pulchellus.

Sixth Division—Acanthopterygii Xiphiiformes.

The upper jaw is produced into a long cuneiform weapon.

These fishes form one small family only, Xiphiidæ.

The “Sword-fishes” are pelagic fishes, occurring in all tropical and sub-tropical seas. Generally found in the open ocean, always vigilant, and endowed with extraordinary strength and velocity, they are but rarely captured, and still more rarely preserved. The species found in the Indian and Pacific Oceans belong to the genus Histiophorus, distinguished from the common Mediterranean Sword-fish, or Xiphias, by the presence of ventral fins, which, however, are reduced to two long styliform appendages. The distinction of the species is beset with great difficulties, owing to the circumstance that but few examples exist in museums, and further, because the form of the dorsal fin, the length of the ventrals, the shape and length of the sword, appear to change according to the age of the individuals. Some specimens or species have only the anterior dorsal rays elevated, the remainder of the fin being very low, whilst in others all the rays are exceedingly elongate, so that the fin, when erected, projects beyond the surface of the water. It is stated that Sword-fishes, when quietly floating with the dorsal fin erect, can sail before the wind, like a boat.

Sword-fishes are the largest of Acanthopterygians, and not exceeded in size by any other Teleostean; they attain to a length of from 12 to 15 feet, and swords have been obtained more than three feet long, and with a diameter of at least three inches at the base. The sword is formed by the prolongation and coalescence of the maxillary and intermaxillary bones; it is rough at its lower surface, owing to the development of rudimentary villiform teeth, very hard and strong, and forms a most formidable weapon. Sword-fishes never hesitate to attack whales and other large Cetaceans, and by repeatedly stabbing these animals generally retire from the combat victorious. The cause which excites them to those attacks is unknown; but they follow this instinct so blindly that they not rarely attack boats or large vessels in a similar manner, evidently mistaking them for Cetaceans. Sometimes they actually succeed in piercing the bottom of a ship, endangering its safety; but as they are unable to execute powerful backward movements they cannot always retract their sword, which is broken off by the exertions of the fish to free itself. A piece of a two-inch plank of a whale-boat, thus pierced by a sword-fish, in which the broken sword still remains, is preserved in the British Museum.

The Rev. Wyatt Gill, who has worked as a missionary for many years in the South Sea Islands, communicates that young Sword-fishes are easily caught in strong nets, but no net is strong enough to hold a fish of six feet in length. Specimens of that size are now and then captured by hook and line, a small fish being used as bait. Individuals with the sword broken off are not rarely observed. Larger specimens cannot be captured by the natives, who are in great fear of them. They easily pierce their canoes, and only too often dangerously wound persons sitting in them.

The Mediterranean Sword-fish is constantly caught in the nets of the Tunny-fishers off the coast of Sicily, and brought to market, where its flesh sells as well as that of the Tunny.

The remarkable changes which Sword-fishes undergo at an early stage of their growth have been noticed above, p. 173 and seq.

Sword-fishes are as old a type as the Berycoids. Their remains have been found in the chalk of Lewes, and more frequently in the London clay of Sheppy, where an extinct genus, Coelorhynchus, has been recognised.

Seventh Division—Acanthopterygii Trichiuriformes.

Body elongate, compressed or band-like; cleft of the mouth wide, with several strong teeth in the jaws or on the palate. The spinous and soft portions of the dorsal fin and the anal are of nearly equal extent, long, many-rayed, sometimes terminating in finlets; caudal fin forked, if present.

Family—Trichiuridæ.

Marine fishes inhabiting the tropical and sub-tropical seas; some of them are surface-fishes, living in the vicinity of the coast, whilst others descend to moderate depths, as the Berycoids. All are powerful rapacious fishes, as is indicated by their dentition.

The oldest of the extinct genera are Enchodus and Anenchelum; they were formerly referred to the Scombroids, but belong to this family. The former has been found in the chalk of Lewes and Mæstricht; the latter is abundant in the Eocene schists of Glaris. Anenchelum is much elongate, and exhibits in the slender structure of its bones the characteristics of a deep-sea fish; it resembles much Lepidopus, but has some long rays in the ventrals. Other Eocene genera are Nemopteryx and Xiphopterus. In the Miocene of Licata in Sicily Trichiuridæ are well represented, viz. by a species of Lepidopus, and by two genera, Hemithyrsites and Trichiurichthys, which are allied to Thyrsites and Trichiurus, but covered with scales.

The following is a complete list of the genera referred to this family:—

Nealotus.—Body incompletely clothed with delicate scales. Small teeth in the jaws and on the palatine bones; none on the vomer. Two dorsal fins, the first continuous and extending to the second; finlets behind the second and anal fins. Each ventral fin represented by a single small spine. A dagger-shaped spine behind the vent. Caudal fin well developed.

One specimen only of this fish (N. tripes), 10 inches long, has been obtained off Madeira; it evidently lives at a considerable depth, and comes to the surface only by accident.

Nesiarchus.—Body covered with small scales. Several strong fangs in the jaws; no teeth on the palate. First dorsal not extending to the second. No detached finlets. Ventrals small, but perfectly developed, thoracic. Caudal fin present. A dagger-shaped spine behind the vent.

A rather large fish (N. nasutus), very rarely found in the sea off Madeira. The two or three specimens found hitherto measure from three to four feet in length. Probably living at the same depth as the preceding genus.

Aphanopus.—Scales none. Two very long dorsal fins; caudal well developed; ventrals none. A strong dagger-shaped spine behind the vent. Strong teeth in the jaws; none on the palate.

One species only is known, named A. carbo from its coal-black colour; it is evidently a deep-sea fish, very rarely obtained in the sea off Madeira. Upwards of four feet long.

Euoxymetopon.—Body naked, very long and thin. Profile of the head regularly decurved from the nape to the snout, the occiput and forehead being elevated and trenchant. Jaws with fangs; palatine teeth present. One dorsal only, continued from the head to the caudal fin, which is distinct. A dagger-shaped spine behind the vent. Pectoral fins inserted almost horizontally, with the lowest rays longest, and with the posterior border emarginate. Ventral fins rudimentary, scale-like.

This is another deep-sea form of this family, but, at present, no observations have been made as regards the exact depth at which it occurs. A specimen has been known since the year 1812; it was found on the coast of Scotland, and described as Trichiurus lepturus. The same species has been re-discovered in the West Indies, where, however, it is also extremely scarce.

Lepidopus.—Body band-like; one single dorsal extends along the whole length of the back; caudal well developed. Ventrals reduced to a pair of scales. Scales none. Several fangs in the jaws; teeth on the palatine bones.

Fig. 192.—Lepidopus caudatus.

The Scabbard-fish (L. caudatus) is rather common in the Mediterranean and warmer parts of the Atlantic, extending northwards to the south coast of England, where it is an occasional visitor, and southwards to the Cape of Good Hope. More recently it has been observed on the coasts of Tasmania and New Zealand. We may, therefore, justly consider it to be a deep-sea fish, which probably descends to the same depth as the preceding allied forms. It grows to a length of five or six feet, but its body is so much compressed that it does not weigh more than as many pounds. It is well known in New Zealand, where it is called “Frost-fish,” and esteemed as the most delicious fish of the colony. A still more attenuated species (L. tenuis) occurs in the sea off Japan, at a depth of some 340 fathoms.

Trichiurus.—Body band-like, tapering into a fine point, without caudal fin. One single dorsal extending the whole length of the back. Ventrals reduced to a pair of scales, or entirely absent. Anal fin rudimentary, with numerous extremely short spines, scarcely projecting beyond the skin. Long fangs in the jaws; teeth on the palatine bones, none on the vomer.

The “Hairtails” belong to the tropical marine fauna, and although generally found in the vicinity of land, they wander frequently out to sea, perhaps merely because they follow some ocean-currents. Therefore they are not rarely found in the temperate zone, the common West Indian species (T. lepturus), for instance, on the coast of England. They attain to a length of about four feet. The number of their vertebræ is very large, as many as 160, and more. Six species are known.

Epinnula.—Body rather elongate, covered with minute scales,[*. see below] The first dorsal fin continuous, with spines of moderate strength, and extending on to the second; finlets none; ventrals well developed. Lateral lines two. Teeth of the jaws strong; palatine teeth, none.

The “Domine” of the Havannah, E. magistralis.

Thyrsites.—Body rather elongate, for the greater part naked. The first dorsal continuous, with the spines of moderate strength, and extending on to the second. From two to six finlets behind the dorsal and anal. Several strong teeth in the jaws; teeth on the palatine bones.

The species of this genus attain to a considerable size (from four to five feet), and are valuable food fishes; Th. atun from the Cape of Good Hope, South Australia, New Zealand, and Chili, is preserved, pickled or smoked. In New Zealand it is called “Barracuda” or “Snoek,” and exported from the colony into Mauritius and Batavia as a regular article of commerce, being worth over £17 a ton; Th. pretiosus, the “Escholar” of the Havannah, from the Mediterranean, the neighbouring parts of the Atlantic, and the West Indies; Th. prometheus from Madeira, Bermuda, St. Helena, and Polynesia; Th. solandri from Amboyna and Tasmania is probably the same as Th. prometheus.

Young specimens of this (or, perhaps, the following) genus have been described as Dicrotus. In them the finlets are not yet detached from the rest of the fin; and the ventral fins, which are entirely obsolete in the adult fish, are represented by a long crenulated spine.

Gempylus.—Body very elongate, scaleless. The first dorsal fin continuous, with thirty and more spines, and extending on to the second. Six finlets behind the dorsal and anal. Several strong teeth in the jaws, none on the palate.

One species (G. serpens), inhabiting considerable depths of the Atlantic and Pacific Oceans.

Family—Palæorhynchidæ.

This family has been formed for two extinct genera: Palæorhynchus from the schists of Glaris, and Hemirhynchus from tertiary formations near Paris. These genera resemble much the Trichiuridæ in their long, compressed body, and long vertical fins, but their jaws, which are produced into a long beak, are toothless, or provided with very small teeth. The dorsal fin extends the whole length of the back, and the anal reaches from the vent nearly to the caudal, which is forked. The ventrals are composed of several rays and thoracic. The vertebræ long, slender, and numerous, and, like all the bones of the skeleton, thin, indicating that these fishes were inhabitants of considerable depths of the ocean. Both the jaws of Palæorhynchus are prolonged into a beak, whilst in Hemirhynchus the upper exceeds the lower in length.

Eighth Division—Acanthopterygii Cotto-scombriformes.

Spines developed, in one of the fins at least. Dorsal fins either continuous or close together; the spinous dorsal, if present, always short; sometimes modified into tentacles, or into a suctorial disk; soft dorsal always long, if the spinous is absent; anal similarly developed as the soft dorsal, and both generally much longer than the spinous, sometimes terminating in finlets. Ventrals, thoracic or jugular, if present, never modified into an adhesive apparatus. No prominent anal papilla.

Marine fishes, with few exceptions.

First Family—Acronuridæ.

Body compressed, oblong or elevated, covered with minute scales. Tail generally armed with one or more bony plates or spines, which are developed with age, but absent in very young individuals. Eye lateral, of moderate size. Mouth small; a single series of more or less compressed, sometimes denticulated, sometimes pointed incisors in each jaw; palate toothless. One dorsal fin, the spinous portion being less developed than the soft; anal with two or three spines; ventral fins thoracic. Air-bladder forked posteriorly. Intestines with more or less numerous circumvolutions. Nine abdominal, and thirteen caudal vertebræ.

Inhabitants of the tropical seas, and most abundant on coral-reefs. They feed either on vegetable substances or on the superficial animal matter of corals.

Extinct species of Acanthurus and Naseus have been discovered in the Monte Bolca formation.

Acanthurus.—Jaws with a single series of lobate incisors, which are sometimes movable. An erectile spine hidden in a groove on each side of the tail. Ventral fins with one spine and generally five rays. Scales ctenoid, sometimes with minute spines. Branchiostegals five.

The fishes of this genus, which sometimes are termed “Surgeons,” are readily recognised by the sharp lancet-shaped spine with which each side of the tail is armed. When at rest the spine is hidden in a sheath; but it can be erected and used by the fish as a very dangerous weapon, by striking with the tail towards the right and left. “Surgeons” occur in all tropical seas, with the exception of the eastern part of the Pacific, where they disappear with the corals. They do not attain to any size, the largest species scarcely exceeding a length of eighteen inches. Many are agreeably or showily coloured, the ornamental colours being distributed in very extraordinary patterns. The larger species are eatable, and some even esteemed as food. It is stated that the fry of some species periodically approaches, in immense numbers, the coasts of some of the South Sea Islands (Caroline Archipelago), and serves as an important article of food to the natives. Nearly fifty species are known.

Fig. 193.—Acanthurus leucosternum, Indian Ocean.

At an early period of their growth these fishes present so different an aspect that they were considered a distinct genus, Acronurus. The form of the body is more circular and exceedingly compressed. No scales are developed, but the skin forms numerous oblique parallel folds. The gill-cover and the breast are shining silvery.

Naseus.—Tail with two (rarely one or three) bony keeled plates on each side (in the adult). Head sometimes with a bony horn or crest-like prominence directed forwards. Ventral fins composed of one spine and three rays. From four to six spines in the dorsal; two anal spines. Scales minute, rough, forming a sort of fine shagreen. Air-bladder forked behind. Intestinal tract with many circumvolutions.

Twelve species are known from the tropical Indo-Pacific, but none of them extend eastwards beyond the Sandwich Islands. In their mode of life these fishes resemble the Acanthuri. Likewise, the young have a very different appearance, and are unarmed, and were described as a distinct genus, Keris. One of the most common species is N. unicornis, which, when adult (22 inches long), has a horn about 2 inches long, whilst it is merely a projection in front of the eye in individuals of 7 inches in length.

Prionurus is an allied genus with a series of several keeled bony laminæ on each side of the tail.

Fig. 194.—Naseus unicornis.

Second Family—Carangidæ.

Body more or less compressed, oblong or elevated, covered with small scales or naked; eye, lateral. Teeth, if present, conical. No bony stay for the præoperculum. The spinous dorsal is less developed than the soft or than the anal, either continuous with, or separated from, the soft portion; sometimes rudimentary. Ventrals thoracic, sometimes rudimentary or entirely absent. No prominent papilla near the vent. Gill-opening wide. Ten abdominal and fourteen caudal vertebræ.

Fig. 195.—Semiophoris velitans.

Inhabitants of tropical and temperate seas. Carnivorous. They appear first in cretaceous formations, where they are represented by Platax and some Caranx-like genera (Vomer and Aipichthys from the chalk of Comen in Istria). They are more numerous in various Tertiary formations, especially in the strata of Monte Bolca, where some still existing genera occur, as Zanclus, Platax, Caranx (Carangopsis), Argyriosus (Vomer), Lichia, Trachynotus. Of the extinct genera the following belong to this family:—Pseudovomer (Licata), Amphistium, Archæus, Ductor, Plionemus (?), and Semiophorus. Equula has been recently discovered in the Miocene marls of Licata in Sicily.

Caranx (including Trachurus).—Body more or less compressed, sometimes sub-cylindrical. Cleft of the mouth of moderate width. The first dorsal fin continuous, with about eight feeble spines, sometimes rudimentary; the soft dorsal and anal are succeeded by finlets in a few species. Two anal spines, somewhat remote from the fin. Scales very small. Lateral line with an anterior curved, and a posterior straight, portion, either entirely or posteriorly only covered by large plate-like scales, several of which are generally keeled, the keel ending in a spine. Dentition feeble. Air-bladder forked posteriorly.

Fig. 196.—Plates of the lateral line of Caranx hippos.

The “Horse-mackerels” are found in abundance in almost all temperate and, especially, tropical seas. Many species wander to other parts of the coast, or to some distance from land, and have thus gradually extended their range over two or more oceanic areas; some are found in all tropical seas. The species described are very numerous, about ninety having been properly characterised and distinguished. Some attain to a length of three feet and more, and all are eatable. They feed on other fish and various marine animals.

Of the most noteworthy species the following may be mentioned:—C. trachurus, the common British Horse-mackerel, distinguished by having the lateral line in its whole length armed with large vertical plates; it is almost cosmopolitan within the temperate and tropical zones of the northern and southern hemispheres. C. crumenophthalmus, C. carangus, and C. hippos, three of the most common sea-fishes, equally abundant in the Atlantic and Indo-Pacific oceans; C. ferdau, from the Indo-Pacific, upwards of three feet in length. C. armatus, ciliaris, gallus, etc., which have an exceedingly short and compressed body, with rudimentary spinous dorsal fin, and with some of the rays of the dorsal and anal prolonged into filaments.

Fig. 197.—Caranx ferdau.

Argyriosus is closely allied to Caranx, especially to the last-named species, but the lateral line has no plates whatever; and the body is scaleless, chiefly of a bright silvery colour.

Two species from the tropical Atlantic.

Micropteryx.—Body much compressed, with prominent trenchant abdomen, covered with small scales; lateral line not shielded; præopercular margin entire. Cleft of the mouth rather small; præorbital of moderate width. The first dorsal continuous, with seven feeble spines. No detached finlets. Small teeth on the vomer and palatine bones.

Micropteryx chrysurus is a semi-pelagic fish, and very common in the tropical Atlantic, less so in the Indian Ocean.

Seriola.—Body oblong, slightly compressed, with rounded abdomen, covered with very small scales; lateral line not shielded; præopercular margin entire. Cleft of the mouth of moderate width, or rather wide. The first dorsal continuous, with feeble spines. No detached finlets. Villiform teeth in the jaws, on the vomer and palatine bones.

These fishes are often called “Yellow-tails,” and occur in nearly all the temperate and tropical seas, sometimes at a great distance from land. Twelve species are known, and the majority have a wide geographical range. The larger grow to a length of from four to five feet, and are esteemed as food, especially at St. Helena, the Cape of Good Hope, in Japan, Australia, and New Zealand.

Seriolella and Seriolichthys, the latter from the Indo-Pacific, and distinguished by a finlet behind the dorsal and anal, are allied genera.

Naucrates.—Body oblong, sub-cylindrical, covered with small scales; a keel on each side of the tail. The spinous dorsal consists of a few short free spines; finlets none. Villiform teeth in the jaws, on the vomer and palatine bones.

The “Pilot-fish” (N. ductor) is a truly pelagic fish, known in all tropical and temperate seas. Its name is derived from its habit of keeping company with ships and large fish, especially Sharks. It is the Pompilus of the ancients, who describe it as pointing out the way to dubious or embarrassed sailors, and as announcing the vicinity of land by its sudden disappearance. It was therefore regarded as a sacred fish. The connection between the Shark and the Pilot-fish has received various interpretations, some observers having perhaps added more sentiment than is warranted by the actual facts. It was stated that the Shark never seized the Pilot-fish, that the latter was of great use to its big companion in conducting it and showing it the way to its food. Dr. Meyen in his “Reise um die Erde” states: “The pilot swims constantly in front of the Shark; we ourselves have seen three instances in which the Shark was led by the Pilot. When the Shark neared the ship the Pilot swam close to the snout, or near one of the pectoral fins of the animal. Sometimes he darted rapidly forwards or sidewards as if looking for something, and constantly went back again to the Shark. When we threw overboard a piece of bacon fastened on a great hook, the Shark was about twenty paces from the ship. With the quickness of lightning the Pilot came up, smelt at the dainty, and instantly swam back again to the Shark, swimming many times round his snout and splashing, as if to give him exact information as to the bacon. The Shark now began to put himself in motion, the Pilot showing him the way, and in a moment he was fast upon the hook.[42] Upon a later occasion we observed two Pilots in sedulous attendance on a Blue Shark, which we caught in the Chinese Sea. It seems probable that the Pilot feeds on the Sharks’ excrements, keeps his company for that purpose, and directs his operations solely from this selfish view.” We believe that Dr. Meyen’s opinion, as expressed in his last words, is perfectly correct. The Pilot obtains a great part of his food directly from the Shark, in feeding on the parasitic crustaceans with which Sharks and other large fish are infested, and on the smaller pieces of flesh which are left unnoticed by the Shark when it tears its prey. The Pilot also, being a small fish, obtains greater security when in company of a Shark, which would keep at a distance all other fishes of prey that would be likely to prove dangerous to the Pilot. Therefore, in accompanying the Shark, the Pilot is led by the same instinct which makes it follow a ship. With regard to the statement that the Pilot itself is never attacked by the Shark all observers agree as to its truth; but this may be accounted for in the same way as the impunity of the swallow from the hawk, the Pilot-fish being too nimble for the unwieldy Shark.

The Pilot-fish does not always leave the vessels on their approach to land. In summer, when the temperature of the sea-water is several degrees above the average, Pilots will follow ships to the south coast of England into the harbour, where they are generally speedily caught. Pilot-fish attain a length of 12 inches only. When very young their appearance differs so much from the mature fish that they have been described as a distinct genus, Nauclerus. This fry is exceedingly common in the open ocean, and constantly obtained in the tow-net; therefore the Pilot-fish retains its pelagic habits also during the spawning season, and some of the spawn found by voyagers floating on the surface is, without doubt, derived from this species.

Chorinemus.—Body compressed, oblong; covered with small scales, singularly shaped, lanceolate, and hidden in the skin. The first dorsal is formed by free spines in small numbers; the posterior rays of the second dorsal and anal are detached finlets. Small teeth in the jaws, on the vomer and palatine bones.

Twelve species are known from the Atlantic and Indo-Pacific; some enter brackish water, whilst others are more numerous at some distance from the shore. They attain to a length of from 2 to 4 feet. In the young, which have been described as Porthmeus, the spines and finlets are connected by membrane with the rest of the fin.

Lichia is an allied genus from the Mediterranean, tropical Atlantic, and the coast of Chili; five species.

Temnodon.—Body oblong, compressed, covered with cycloid scales of moderate size. Cleft of the mouth rather wide. Jaws with a series of strong teeth; smaller ones on the vomer and the palatine bones. The first dorsal with eight feeble spines connected by membrane; finlets none. Lateral line not shielded. The second dorsal and anal covered with very small scales.

Temnodon saltator, sometimes called “Skip-jack,” is spread over nearly all the tropical and sub-tropical seas; it frequents principally the coasts, but is also met with in the open sea. On the coasts of the United States it is well known by the name of “Blue-fish,” being highly esteemed as food, and furnishing excellent sport. It is one of the most rapacious fishes, destroying an immense number of other shore-fishes, and killing many more than they can devour. It grows to a length of 5 feet, but the majority of those brought to market are not half that length.

Trachynotus.—Body more or less elevated, compressed, covered with very small scales. Cleft of the mouth rather small, with short convex snout. Opercles entire. The first dorsal composed of free spines in small number. No finlets. Teeth always small, and generally lost with age.

Ten species are known from the tropical Atlantic and Indo-Pacific; they rarely exceed a length of 20 inches. Some of the most common marine fishes belong to this genus, for instance T. ovatus, which ranges over the entire tropical zone.

Pammelas (perciformis) is allied to the preceding genus; from the coast of New York.

Fig. 198.—Magnified scale of Psettus argenteus.

Psettus.—Body much compressed and elevated; snout rather short. One dorsal, entirely covered with scales, with seven or eight spines; anal fin with three. Ventrals very small, rudimentary. Teeth villiform; no teeth on the palate. Scales small, ctenoid.

Only three species are known; one, P. sebæ, from the west coast of Africa, the two others from the Indo-Pacific. P. argenteus is a very common fish, attaining to a length of about 10 inches.

Fig. 199.—Psettus argenteus.

Platax.—Body much compressed and elevated; snout very short. One dorsal, with the spinous portion nearly entirely hidden, and formed by from three to seven spines; anal with three. Ventrals well developed, with one spine and five rays. Teeth setiform, with an outer series of rather larger teeth, notched at the top; palate toothless. Scales of moderate size or rather small.

These fishes are called “Sea-bats,” from the extraordinary length of some portion of their dorsal and anal fins and of their ventrals. These long lobes are generally of a deep black colour. In mature and old individuals the fin-rays are much shorter than in the young, which have been described as distinct species. There are probably not more than seven species of “Sea-bats,” if so many, and they all belong to the Indian Ocean and Western Pacific, where they are very common.

Zanclus.—Body much compressed and elevated. One dorsal, with seven spines, the third of which is very elongate. No teeth on the palate. Scales minute, velvety.

One species (Z. cornutus), which is extremely common in the Indo-Pacific. It is easily recognised by its snout, which is produced like that of Chelmon, and by the broad black bands crossing the yellow ground-colour. It attains to a length of eight inches, and undergoes during growth similar changes as Acanthurus.

Anomalops.—Body oblong, covered with small, rough scales. Snout very short, convex, with wide cleft of the mouth. Eyes very large; below the eye, in a cavity of the infraorbital ring, there is a glandular phosphorescent organ. Villiform teeth in the jaws and on the palatine bones, none on the vomer. First dorsal fin short, with a few feeble spines connected by membrane.

This genus, of which one species only is known (A. palpebratus), represents the family of Horse-Mackerels in the depths of the sea; but we do not know, at present, at what depth it lives. Only six specimens have been obtained hitherto from the vicinity of Amboyna, the Fidji, and Paumotu Islands; the largest was twelve inches long.

Capros.—Body compressed and elevated. Mouth very protractile. Scales rather small, spiny. First dorsal with nine spines, anal with three. Ventral fins well developed. Minute teeth in the jaws and on the vomer; none on the palatine bones.

The “Boar-fish” (C. aper) is common in the Mediterranean, and not rarely found on the south coast of England.

Allied are Antigonia and Diretmus, known from a few individuals obtained at Madeira and Barbadoes; they are probably fishes which but rarely come to the surface.

Equula.—Body more or less compressed, elevated or oblong, covered with small, deciduous, cycloid scales. Mouth very protractile. Minute teeth in the jaws; none on the palate. One dorsal. Formula of the fins: D. 8/1516, A. 3/14, V. 1/5. The lower præopercular margin serrated.

Fig. 200.—Equula edentula.

Small species, abundant in the Indo-Pacific, disappearing on the coasts of Japan and Australia. Some eighteen species have been described.

Gazza is very similar to Equula, but armed with canine teeth in the jaws.

Other genera referred to this family are Lactarius (L. delicatulus, common, and eaten on the East Indian coasts), Seriolella, Paropsis, and Platystethus.

Third Family—Cyttidæ.

Body elevated, compressed, covered with small scales, or with bucklers, or naked; eye lateral. Teeth conical, small. No bony stay for the præoperculum. Dorsal fin composed of two distinct portions. Ventrals thoracic. No prominent papilla near the vent. Gill-opening wide. More than ten abdominal and more than fourteen caudal vertebræ.

The fishes of the “Dory” family are truly marine, and inhabit the temperate zone of the Northern and Southern Hemispheres. Some fossils from tertiary formations (one from Licata) belong to the genus Zeus.

Zeus.—A series of bony plates runs along the base of the dorsal and anal fins; another series on the abdomen. Three or four anal spines.

“John Dorys” are found in the Mediterranean, on the eastern temperate shores of the Atlantic, on the coasts of Japan and Australia. Six species are known, all of which are highly esteemed for the table. The English name given to one of the European species (Zeus faber) seems to be partly a corruption of the Gascon “Jau,” which signifies cock, “Dory” being derived from the French Dorée, so that the entire name means Gilt-Cock. Indeed, in some other localities of Southern Europe it bears the name of Gallo. The same species occurs also on the coasts of South Australia and New Zealand. The fishermen of Roman Catholic countries hold this fish in special respect, as they recognise in a black round spot on its side the mark left by the thumb of St. Peter when he took the piece of money from its mouth.

Fig. 201.—Cyttus australis.

Cyttus.—Body covered with very small scales; no osseous bucklers on any part of the body. Two anal spines; ventral fins composed of one spine and six or eight rays.

Three species are known from Madeira, South Australia, and New Zealand.

Fourth Family—Stromateidæ.

Body more or less oblong and compressed, covered with very small scales; eye lateral. Dentition very feeble; œsophagus armed with numerous horny, barbed processes. No bony stay for the præoperculum. Dorsal fin single, long, without distinct spinous division. More than ten abdominal and more than fourteen caudal vertebræ.

This small family consists of strictly marine and partly pelagic species referred to two genera, Stromateus and Centrolophus. The former lacks ventral fins, at least in the adult stage, and is represented by about ten species in almost all the tropical and warmer seas. Centrolophus, hitherto known from two or three European species only (of which one occasionally reaches the south coast of England, where it is named “Black-fish”), has recently been discovered on the coast of Peru, and has probably a much wider range.

Fifth Family—Coryphænidæ.

Body compressed; eye lateral. Teeth small, conical, if present; œsophagus smooth. No bony stay for the præoperculum. Dorsal fin single, long, without distinct spinous division. More than ten abdominal and more than fourteen caudal vertebræ.

All the members of this family have pelagic habits. Representatives of it have been recognized in some fossil remains: thus Goniognathus from the Isle of Sheppey, and the living genus Mene (Gastrocnemus) at Monte Bolca.

Coryphæna.—Body compressed, rather elongate; adult specimens with a high crest on the top of the head; cleft of the mouth wide. A single dorsal extending from the occiput almost to the caudal, which is deeply forked; no distinct dorsal and anal spines. The ventrals are well developed, and can be received in a groove on the abdomen. Scales very small. Rasp-like teeth in the jaws, on the vomer and the palatine bones. Air-bladder absent.

Fig. 202.—Dolphin from the Atlantic.

Generally, though by misapplication of the name, called “Dolphins.” About six species are known, each of which is probably distributed over all the tropical and sub-tropical seas. Strictly pelagic in their habits, they are most powerful swimmers; they congregate in shoals, and pursue unceasingly the Flying-Fish, which try to escape their enemies by long flying leaps. They attain to a length of six feet, and are eagerly caught by sailors on account of their well-flavoured flesh. The beauty of their, unfortunately fugitive, colours has ever been a subject of admiration. As far as the colours are capable of description, those of the common species (C. hippurus), which is often seen in the Mediterranean, are silvery blue above, with markings of a deeper azure, and reflections of pure gold, the lower parts being lemon-yellow, marked with pale blue. The pectoral fins are partly lead colour, partly yellow; the anal is yellow, the iris of the eye golden. These iridescent colours change rapidly whilst the fish is dying, as in the Mackerel. The form of the body, and especially of the head, changes considerably with age. Very young specimens, from one to six inches in length, are abundant in the open sea, and frequently obtained in the tow-net. Their body is cylindrical, their head as broad as high, and the eye relatively very large, much longer than the snout. As the fish grows the body is more compressed, and finally a high crest is developed on the head, and the anterior part of the dorsal fin attains a height equal to that of the body.

Brama.—Body compressed, and more or less elevated, covered with rather small scales; cleft of the mouth very oblique, with the lower jaw longest. Dorsal and anal fins many-rayed, the former with three or four, the latter with two or three, spines; caudal deeply forked. Ventrals thoracic, with one spine and five rays. The jaws with an outer series of stronger teeth.

Pelagic fishes which, like the allied genus Taractes, range over almost all the tropical and temperate seas.

Lampris.—Body compressed and elevated, covered with very small deciduous scales; cleft of the mouth narrow. A single dorsal, without a spinous portion. Ventrals composed of numerous rays. Teeth none.

Fig. 203.—Lampris luna.

The “Sun-fish” (L. luna) is one of the most beautiful fishes of the Atlantic. It attains to the large size of four feet in length, is bluish on the back, with round silvery spots, which colour prevails on the lower parts; the fins are of a deep scarlet. It is said to be excellent eating. It is a pelagic fish, not rare about Madeira, but extending far northwards in the Atlantic; it seems to be rarer in the Mediterranean. All the specimens hitherto obtained were full-grown or nearly so. The skeleton exhibits several peculiarities, viz. an extraordinary development and dilatation of the humeral arch, and great strength of the numerous and closely-set ribs.

Other Coryphænoid genera are Pteraclis, Schedophilus, Diana, Ausonia, and Mene; all pelagic forms.

Sixth Family—Nomeidæ.

Body oblong, more or less compressed, covered with cycloid scales of moderate size; eye lateral. No bony stay for the præoperculum. Dorsal fin with a distinct spinous portion separated from the soft; sometimes finlets; caudal forked. More than ten abdominal, and more than fourteen caudal vertebræ.

Marine fishes; pelagic, at least when young.

Fig. 204.—Gastrochisma melampus.

Gastrochisma.—Cleft of the mouth wide. Finlets behind the dorsal and anal fins. The ventral fins are exceedingly broad and long, and can be completely concealed in a fold of the abdomen.

G. melampus, from the coast of New Zealand; scarce.

Nomeus.—Cleft of the mouth narrow. No finlets. The ventral fin is long and broad, attached to the abdomen by a membrane, and can be received in a fissure of the abdomen.

N. gronovii is a common pelagic fish in the Atlantic and Indian Oceans; of small size.

Other genera belonging to this family are Psenes and Cubiceps.

Seventh Family—Scombridæ.

Body oblong, scarcely compressed, naked or covered with small scales; eye lateral. Dentition well developed. No bony stay for the præoperculum. Two dorsal fins; generally finlets. Ventrals thoracic, with one spine and five rays. More than ten abdominal, and more than fourteen caudal vertebræ.

The fishes of the “Mackerel” family are pelagic forms, abundant in all the seas of the tropical and temperate zones. They are one of the four families of fishes which are the most useful to man, the others being the Gadoids, Clupeoids, and Salmonoids. They are fishes of prey, and unceasingly active, their power of endurance in swimming being equal to the rapidity of their motions. Their muscles receive a greater supply of blood-vessels and nerves than in other fishes, and are of a red colour, and more like those of birds or mammals. This energy of muscular action causes the temperature of their blood to be several degrees higher than in other fishes. They wander about in shoals, spawn in the open sea, but periodically approach the shore, probably in the pursuit of other fishes on which they feed.[43]

Scombridæ are well represented in tertiary formations: in the Eocene schists of Glaris two extinct genera, Palimphyes and Isurus, have been discovered. In Eocene and Miocene formations Scomber, Thynnus, and Cybium are not uncommon.

Scomber.—The first dorsal continuous, with feeble spines; five or six finlets behind the dorsal and anal. Scales very small, and equally covering the whole body. Teeth small. Two short ridges on each side of the caudal fin.

Mackerels proper are found in almost all temperate and tropical seas, with the exception of the Atlantic shores of temperate South America, where they have not been found hitherto. In Europe, and probably also on the coast of England, three species occur: S. scomber, the common Mackerel, which lacks an air-bladder; S. pneumatophorus, a more southern species, with an air-bladder; and S. colias, like the former, but with a somewhat different coloration, and often called “Spanish” Mackerel. On the Cape of Good Hope, in Japan, on the coast of California, in South Australia, and New Zealand, Mackerels are abundant, which are either identical with, or very closely allied to, the European species. On the coasts of the United States the same species occur which tenant the western parts of the Atlantic. Altogether seven species are known.

Fig. 205.—Thynnus thynnus.

Thynnus.—The first dorsal continuous, with the spines rather feeble; from six to nine finlets behind the dorsal and anal. Scales of the pectoral region crowded, forming a corslet. Teeth rather small. A longitudinal keel on each side of the tail.

The best-known species of this genus is the “Tunny” (Thynnus thynnus), abundant in the Mediterranean, and ranging to the south coast of England and to Tasmania. It is one of the largest fishes of the ocean, attaining to a length of 10 feet, and to a weight of more than 1000 lbs. The fishery of the Tunny is systematically carried on in the Mediterranean, and dates from the most remote antiquity. Its salted preparation was esteemed by the Romans under the name of Saltamentum sardicum. Its flesh is extensively eaten now, fresh as well as preserved.

Thynnus pelamys, or the “Bonito,” is equally well known, and ranges over all the tropical and temperate seas; it eagerly pursues the Flying-fish, and affords welcome sport and food to the sailor. In its form it resembles the Tunny, but is more slender and rarely above three feet long.

Some of the other species are provided with very long pectoral fins, and generally called by sailors “Albacore.” They are said to grow to a length of six feet; Bennett in his “Whaling Voyage,” vol. ii. p. 278, makes the following observations on Th. germo, from the Pacific: “Ships when cruising slowly in the Pacific Ocean, are usually attended by myriads of this fish for many successive months. A few days’ rapid sailing is, nevertheless, sufficient to get rid of them, however numerous they may be, for they seldom pay more than very transient visits to vessels making a quick passage. When the ship is sailing with a fresh breeze they swim pertinaciously by her side and take the hook greedily, but should she be lying motionless or becalmed they go off to some distance in search of prey, and cannot be prevailed upon to take the most tempting bait the sailor can devise. It is probably as a protection from their chief enemy, the Sword-fish, that they seek the society of a ship. I am not aware that the Shark is also their enemy; but they seemed to have an instinctive dread of this large fish, and when it approached the ship, would follow it in shoals, and annoy it in the same manner as the smaller birds may be seen to annoy those of a larger and predaceous kind, as the hawk or owl. They are very voracious and miscellaneous feeders. Flying-fish, Calmars, and small shoal-fish are their most natural food; though they do not refuse the animal offal from a ship. Amongst the other food contained in their maw, we have found small Ostracions, File-fish, Sucking-fish, Janthina shells, and pelagic crabs; in one instance a small Bonita, and in a second a Dolphin eight inches long, and a Paper-nautilus shell containing its sepia-tenant. It was often amusing to watch an Albacore pursuing a Flying-fish, and to mark the precision with which it swam beneath the feeble æronaut, keeping him steadily in view, and preparing to seize him at the moment of his descent. But this the Flying-fish would often elude by instantaneously renewing his leap, and not unfrequently escape by extreme agility.”

Pelamys.—The first dorsal continuous, with the spines rather feeble; from seven to nine finlets behind the dorsal and anal. Scales of the pectoral region forming a corslet. Teeth moderately strong. A longitudinal keel on each side of the tail.

Five species are known, of which P. sarda is common in the Atlantic and Mediterranean.

Auxis.—Differing from the preceding two genera in having very small teeth in the jaws only, none on the palate.

Auxis rochei common in the Atlantic, Mediterranean, and Indian Ocean.

Cybium.—The first dorsal continuous, with the spines rather feeble; generally more than seven finlets behind the dorsal and anal. Scales rudimentary or absent. Teeth strong; a longitudinal keel on each side of the tail.

Twelve species from the tropical Atlantic and Indian Ocean; frequenting more the coast-region than the open sea; attaining to a length of four or five feet.

Elacate.—Body covered with very small scales; head depressed; cleft of the mouth moderately wide; no keel on the tail. The spinous dorsal is formed by eight small free spines; finlets none. Villiform teeth in the jaws, on the vomer and the palatine bones.

Elacate nigra, a coast fish common in the warmer parts of the Atlantic and the Indian Ocean.

Echeneis.—The spinous dorsal fin is modified into an adhesive disk, occupying the upper side of the head and neck.

This genus is closely allied to the preceding, from which it differs only by the transformation of the spinous dorsal fin into a sucking organ. The spines being composed of two halves, each half is bent down towards the right and the left, forming a support to a double series of transverse lamellæ, rough on their edges, the whole disk being of an oval shape and surrounded by a membranous fringe. Each pair of lamellæ is formed out of one spine, which, as usual, is supported at the base by an interneural spine. By means of this disk the “Sucking-fishes” or “Suckers” are enabled to attach themselves to any flat surface, a series of vacuums being created by the erection of the usually recumbent lamellæ. The adhesion is so strong that the fish can only be dislodged with difficulty, unless it is pushed forward by a sliding motion. The Suckers attach themselves to sharks, turtles, ships, or any other object which serves their purpose. They cannot be regarded as parasites, inasmuch as they obtain their food independently of their host. Being bad swimmers they allow themselves to be carried about by other animals or vessels endowed with a greater power of locomotion. They were as well known to the ancients as they are to the modern navigators. Aristotle and Aelian mention the Sucker under the name of φθεὶρ, or the Louse; “In the sea between Cyrene and Egypt there is a fish about the Dolphin (Delphinus), which they call the Louse; this becomes the fattest of all fishes, because it partakes of the plentiful supply of food captured by the Dolphin.” Later writers, then, repeat a story, the source of which is unknown, viz. that the “Remora” is able to arrest vessels in their course, a story which has been handed down to our own time. It need not be stated that this is an invention, though it cannot be denied that the attachment of one of the larger species may retard the progress of a sailing vessel, especially when, as is sometimes the case, several individuals accompany the same ship. An account of a somewhat ingenious way of catching sleeping turtles by means of a Sucking-fish held by a ring fastened round its tail, appears to have originated rather from an experiment than from regular practice.

Ten different species are known, of which Echeneis remora and Echeneis naucrates are the most common. The former is short and grows to a length of eight inches only, the latter is a slender fish, not rarely found three feet long. The bulkiest is Echeneis scutata, which attains to a length of two feet; individuals of that size weighing about eight lbs.

The number of pairs of lamellæ varies in the various species, from 12 to 27. The caudal fin of some of the species undergoes great changes with age. In young specimens the middle portion of the fin is produced into a long filiform lobe. This lobe becomes gradually shorter, and the fin shows a rounded margin in individuals of middle age. When the fish approaches the mature state, the upper and lower lobes are produced, and the fin becomes subcrescentic or forked.

[See Günther, “On the History of Echeneis.” Ann. and Mag. Nat. Hist., 1860.]

Eighth Family.—Trachinidæ.

Body elongate, low, naked or covered with scales. Teeth small, conical. No bony stay for the præoperculum. One or two dorsal fins, the spinous portion being always shorter and much less developed than the soft; the anal similarly developed as the soft dorsal; no finlets. Ventrals with one spine and five rays. Gill-opening more or less wide. Ten or more than ten abdominal, and more than fourteen caudal vertebræ.

Carnivorous coast-fishes of small size, found in every quarter of the globe, but scarcely represented in the Arctic zone (Trichodon); on the other hand, they are rather numerous towards the Antarctic circle. All are bad swimmers, generally moving along the bottom in small depths. Only one genus (Bathydraco) is known from the deep-sea.

A genus which shows the principal characters of this family (Callipteryx), has been found in the tertiary deposits of Monte Bolca; it is scaleless. A second genus, Trachinopsis, has been recently described by Sauvage from the Upper Tertiary of Lorca in Spain; and a third (Pseudoeleginus) from the Miocene of Licata.

This family may be subdivided into five groups:—

1. In the Uranoscopina the eyes are on the upper surface of the head, directed upwards; the lateral line is continuous.

Uranoscopus.—Head large, broad, thick, partly covered with bony plates; cleft of the mouth vertical. Scales very small. Two dorsal fins, the first with from three to five spines; ventrals jugular; pectoral rays branched. Villiform teeth in the jaws, on the vomer and palatine bones; no canines. Generally a long filament below and before the tongue. Gill-cover armed.

The position of the eyes on the upper surface of the head, which these fishes have in common with many others, is well expressed by the name Uranoscopus (Stare-gazer). Their eyes are very small, and can be raised or depressed at the will of the fish. They are inactive fishes, generally lying hidden at the bottom between stones, watching for their prey. The delicate filament attached to the bottom of their mouth, and playing in front of it in the current of water which passes through the mouth, serves to lure small animals within reach of the fish. Eleven species are known from the Indo-Pacific and Atlantic, and one (U. scaber) from the Mediterranean; they attain rarely a length of twelve inches.

Leptoscopus.—Form of the head as in Uranoscopus, but entirely covered with a thin skin. Scales small, cycloid. One continuous dorsal; ventrals jugular; pectoral rays branched. Villiform teeth in both jaws, on the vomer and palatine bones; canines none. No oral filament. Gill-cover unarmed.

Fig. 206.—Leptoscopus macropygus.

Leptoscopus macropygus, not rare on the coast of New Zealand.

Other genera of Stare-gazers are Agnus from the Atlantic coasts of North America; Anema from the Indian Ocean and New Zealand; and Kathetostoma from Australia and New Zealand.

2. In the Trachinina the eyes are more or less lateral; the lateral line is continuous; and the intermaxillary without a larger tooth on its posterior portion.

Trachinus.—Cleft of the mouth very oblique; eye lateral, but directed upwards. Scales very small, cycloid. Two dorsal fins, the first short, with six or seven spines; ventrals jugular; the lower pectoral rays simple. Villiform teeth in the jaws, on the vomer and palatine bones. Præorbital and præoperculum armed.

The “Weevers” are common fishes on the European coasts, and but too well known to all fishermen; singularly enough they do not extend across the Atlantic to the American coast, but reappear on the coast of Chili! Wounds by their dorsal and opercular spines are much dreaded, being extremely painful, and sometimes causing violent inflammation of the wounded part. No special poison-organ has been found in these fishes, but there is no doubt that the mucous secretion in the vicinity of the spines has poisonous properties. The dorsal spines as well as the opercular spine have a deep double groove in which the poisonous fluid is lodged, and by which it is inoculated in the punctured wound. On the British coasts two species occur, T. draco, the Greater Weever, attaining to a length of twelve inches, and T. vipera, the Lesser Weever, which grows only to half that size.

Champsodon.—Body covered with minute granular scales; lateral lines two, with numerous vertical branches. Cleft of the mouth wide, oblique. Eye lateral, but directed upwards. Two dorsal fins; ventral fins jugular; pectoral rays branched. Teeth in the jaws in a single series, thin, long, of unequal size. Teeth on the vomer, none on the palate. Gill-openings exceedingly wide. Præoperculum with a spine at the angle and a fine serrature on the posterior margin.

Champsodon vorax is not uncommon at small depths off the Philippine Islands, Admiralty Islands, and in the Arafura Sea.

Percis.—Body cylindrical, with small ctenoid scales; cleft of the mouth slightly oblique; eye lateral, but directed upwards. Dorsal fins more or less continuous, the spinous with four or five short stiff spines; ventrals a little before the pectorals. Villiform teeth in the jaws, with the addition of canines; teeth on the vomer, none on the palatines. Opercles feebly armed.

Fifteen species; small, but prettily coloured shore-fishes of the Indo-Pacific.

Sillago.—Body covered with rather small, ctenoid scales. Cleft of the mouth small, with the upper jaw rather longer; eye lateral, large. Two dorsals, the first with from nine to twelve spines; ventrals thoracic. Villiform teeth in the jaws, and on the vomer, none on the palatine bones. Operculum unarmed; præoperculum serrated. The bones of the head with wide muciferous channels.

Eight species; small, plain-coloured shore-fishes, common in the Indian Ocean to the coasts of Australia.

Bovichthys.—Head broad and thick; cleft of the mouth horizontal, with the upper jaw rather longer; eye lateral, more or less directed upwards. Scales none. Two separate dorsal fins, the first with eight spines; ventrals jugular; the lower pectoral rays simple. Villiform teeth in the jaws, on the vomer and the palatine bones; no canines. Operculum with a strong spine; præorbital and præoperculum not armed.

Three species are known from the South Pacific.

Fig. 207.—Head of Bovichthys variegatus, from New Zealand.

Bathydraco.—Body elongate, sub-cylindrical; head depressed, with the snout much elongate, spatulate; mouth wide, horizontal, with the lower jaw prominent; eyes very large, lateral, close together. Scales very small, imbedded in the skin. Lateral line wide, continuous. One dorsal fin; ventrals jugular; the lower pectoral rays branched. Teeth in the jaws in villiform bands; none on the vomer or the palatine bones. Opercles unarmed; ten branchiostegals; the gill-membranes free from the isthmus, and but slightly united in front. Air-bladder none.

A deep-sea fish, found at a depth of 1260 fathoms in the Antarctic Ocean (south of Heard Island).

Chænichthys.—Head very large, with the snout spatulate, and with the cleft of the mouth very wide. Eye lateral. Scales none; lateral line sometimes with granulated scutes. Two dorsals, the first with seven spines; ventrals jugular. Jaws with rasp-like teeth; palate toothless.

Chænichthys rhinoceratus from Kerguelen’s Land (see Fig. [108], p. 291); and Ch. esox from the Straits of Magelhaen.

Other genera belonging to this group are Aphritis, Acanthaphritis, Eleginus, Chænichthys, and Chimarrhichthys from the South Pacific and Antarctic zone; Cottoperca from the west coast of Patagonia; Percophis from the coast of Southern Brazil; and Trichodon from the coast of Kamtschatka.

3. In the Pinguipedina the body is covered with small scales; the eye lateral; the lateral line continuous; and the intermaxillary is armed with a larger tooth on its posterior portion, as in many Labroids.

Two genera, Pinguipes and Latilus, from various parts of tropical and sub-tropical seas, belong to this group.

4. In the Pseudochromides, the lateral line is interrupted or not continued to the caudal fin; they have one continuous dorsal only.

These fishes are inhabitants of coral reefs or coasts: Opisthognathus, Pseudochromis, Cichlops, and Pseudoplesiops.

5. In the Nototheniina the lateral line is interrupted; and the dorsal fin consists of two separate portions.

They (with others) represent in the Antarctic zone the Cottoids of the Northern Hemisphere: they have the same habits as their northern analogues. In Notothenia, which on the southern extremity of South America, in New Zealand, Kerguelen’s Land, etc., is represented by about twenty species, the body is covered with ctenoid scales, and the bones of the head are unarmed; whilst Harpagifer, a small species with a similar range as Notothenia, has the body naked, and the operculum and sub-operculum armed with long and strong spines.

Ninth Family—Malacanthidæ.

Body elongate, with very small scales; mouth with thick lips; a strong tooth posteriorly on the intermaxillary. Dorsal and anal fins very long, the former with a few simple rays anteriorly; ventrals thoracic, with one spine and five rays. Gill-opening wide, with the gill-membranes united below the throat. Ten abdominal and fourteen caudal vertebræ.

One genus only, Malacanthus, with three species from tropical seas.

Tenth Family—Batrachidæ.

Head broad and thick; body elongate, compressed behind; skin naked or with small scales. No bony stay for the præoperculum. Teeth conical, small or of moderate size. The spinous dorsal consists of two or three spines only; the soft and the anal long. Ventrals jugular, with two soft rays; pectorals not pediculated. Gill-opening a more or less vertical slit before the pectoral, rather narrow.

Carnivorous fishes, of small size, living on the bottom of the sea near the coast in the tropical zone, some species advancing into the warmer parts of the temperate zones.

Batrachus.—The spinous dorsal is formed by three stout spines. Gill-covers armed with spines. Circumference of the mouth and other parts of the head frequently provided with small skinny tentacles.

Some of the fishes of this genus possess a subcutaneous spacious cavity behind the base of the pectoral fin, the inside of which is coated with a reticulated mucous membrane. It opens by a foramen in the upper part of the axil.—This apparatus is the same which is found in many Siluroid fishes, and which has been noticed above, p. 192. There cannot be any doubt that it is a secretory organ, but whether the secretion has any poisonous properties, as in the Siluroids, or as in Thalassophryne, has not been determined. No instance of poisonous wounds having been inflicted by these fishes is on record. Twelve species are known, the distribution of which coincides with that of the family; one very fine species, B. didactylus, occurs in the Mediterranean.

Thalassophryne.—The spinous dorsal is formed by two spines only, each of which is hollow, like the opercular spine, and conveys the contents of a poison-bag situated at its base. Canine teeth none.

Fig. 208.—Thalassophryne reticulata.

Two species are known from the Atlantic and Pacific coasts of Central America. The poison-apparatus is more perfectly developed than any other known at present in the class of fishes; it has been described above, p. 192. The species figured, Th. reticulata, is not uncommon at Panama, and attains to a length of fifteen inches.

Porichthys.—Two small dorsal spines; a canine tooth on each side of the vomer.

Two species, from the Atlantic and Pacific sides of Central and South America.

Eleventh Family—Psychrolutidæ.

Body rather elongate, naked; head broad. Spinous dorsal separate or absent. Ventral fins close together, thoracic, composed of a few rays. Teeth small. Three gills and a half; pseudobranchiæ well developed; gill-openings of moderate width, the gill-membranes being attached to the isthmus.

Of this family only two representatives are known, viz. Psychrolutes paradoxus, from Vancouver’s Islands, without first dorsal fin; and Neophrynichthys latus, from New Zealand, with two dorsal fins. Both are very scarce marine fishes.

Twelfth Family—Pediculati.

Head and anterior part of the body very large, without scales. No bony stay for the præoperculum. Teeth villiform or rasp-like. The spinous dorsal is advanced forwards, composed of a few more or less isolated spines, often transformed into tentacles; or entirely absent. Ventral fins jugular, with four or five soft rays, sometimes absent. The carpal bones are prolonged, forming a sort of arm, terminating in the pectoral. Gill-opening reduced to a small foramen, situated in or near the axil. Gills two and a half, or three, or three and a half; pseudobranchiæ generally absent.

This family contains a larger number of bizarre forms than any other; and there is, perhaps, none in which the singular organisation of the fish is more distinctly seen to be in consonance with its habits. Pediculates are found in all seas. The habits of all are equally sluggish and inactive; they are very bad swimmers; those found near the coasts lie on the bottom of the sea, holding on with their arm-like pectoral fins by seaweed or stones, between which they are hidden; those of pelagic habits attach themselves to floating seaweed or other objects, and are at the mercy of wind and current. A large proportion of the genera, therefore, have gradually found their way to the greatest depths of the ocean; retaining all the characteristics of their surface-ancestors, but assuming the modifications by which they are enabled to live in abyssal depths.

Lophius.—Head exceedingly large, broad, depressed, with the eyes on its upper surface; cleft of the mouth very wide. Jaws and palate armed with rasp-like depressible teeth of unequal size. Body naked; bones of the head armed with numerous spines. The three anterior dorsal spines are isolated, situated on the head, and modified into long tentacles; the three following spines form a continuous fin; the soft dorsal and anal short. Gills three. Young individuals have the tentacles beset with lappets, and most of the fin-rays prolonged into filaments.

These fishes are well known under the names “Fishing-Frog,” “Frog-fishes,” “Anglers,” or “Sea-devils.” They are coast-fishes, living at very small depths. Four species are known: the British species (L. piscatorius) found all round the coasts of Europe and Western North America, and on the Cape of Good Hope; a second (Mediterranean) species, L. budegassa; L. setigerus from China and Japan; and L. naresii from the Admiralty Islands.

Fig. 209.—Lophius piscatorius.

Fig. 210.—A young Fishing-Frog.

The habits of all these species are identical. The wide mouth extends all round the anterior circumference of the head, and both jaws are armed with bands of long pointed teeth, which are inclined inwards, and can be depressed so as to offer no impediment to an object gliding towards the stomach, but prevent its escape from the mouth. The pectoral and ventral fins are so articulated as to perform the functions of teeth, the fish being enabled to move, or rather to walk, on the bottom of the sea, where it generally hides itself in the sand, or amongst seaweed. All round its head, and also along the body, the skin bears fringed appendages, resembling short fronds of seaweed; a structure which, combined with the extraordinary faculty of assimilating the colours of the body to its surroundings, assists this fish greatly in concealing itself in places which it selects on account of the abundance of prey. To render the organisation of these creatures perfect in relation to their wants, they are provided with three long filaments inserted along the middle of the head, which are, in fact, the detached and modified three first spines of the anterior dorsal fin. The filaments most important in the economy of the fishing-frogs is the first, which is the longest, terminates in a lappet, and is movable in every direction. There is no doubt that the Fishing-frog, like many other fish provided with similar appendages, plays with this filament as with a bait, attracting fishes, which, when sufficiently near, are ingulfed by the simple act of the Fishing-frog opening its gape. Its stomach is distensible in an extraordinary degree, and not rarely fishes have been taken out of it quite as large and heavy as their destroyer. The British species grows to a length of more than five feet; specimens of three feet are common. Baird records that the spawn of the same species has been observed as a floating sheet of mucus, of from some 60 to 100 square feet.

Ceratias.—Head and body much compressed and elevated; cleft of the mouth wide, subvertical. Eyes very small. Teeth in the jaws rasp-like, depressible; palate toothless. Skin covered with numerous prickles. The spinous dorsal is reduced to two long isolated spines, the first on the middle of the head, the second on the back. The soft dorsal and anal short; caudal very long. Ventrals none; pectorals very short. Two and a half gills. Skeleton soft and fibrous.

Ceratias holbölli, a deep-sea fish; only a few examples have been found near the coast of Greenland, and from the mid-Atlantic; the latter at a depth of 2400 fathoms. Deep black.

Himantolophus.—Head and body compressed and elevated; cleft of the mouth wide, oblique. Eyes very small. Teeth of the jaws rasp-like, depressible; palate toothless. Skin with scattered conical tubercles. The spinous dorsal is reduced to a single tentacle on the head. The soft dorsal, anal, caudal, and pectoral short. Ventrals none. Three and a half gills. Skeleton soft and fibrous.

This is another deep-sea form, hitherto found in very few examples in the Arctic and Mid-Atlantic Oceans. The single tentacle is beset with many long filaments at its extremity, thus answering the same purpose which is attained by a greater number of tentacles. Deep black.

Melanocetus.—Head and body compressed; head very large; cleft of the mouth exceedingly wide, vertical. Eyes very small. Teeth of the jaws and vomer rasp-like, depressible. Skin smooth. The spinous dorsal is reduced to a single filament placed on the head. The soft dorsal and anal short. Ventrals none.

Fig. 211.—Melanocetus johnsonii.

Two species are known from the Atlantic: M. bispinossus and M. johnsonii, obtained at depths of from 360 to 1800 fathoms. The specimen figured was not quite four inches long, and contained in its stomach, rolled up spirally into a ball, a Scopeline fish which measured 7½ inches in length and one inch in depth.

Oneirodes.—A deep-sea fish from the Arctic Ocean, differing from the preceding in possessing a second isolated dorsal ray on the back.

Antennarius.—Head very large, high, compressed; cleft of the mouth vertical or subvertical, of moderate width. Jaws and palate armed with rasp-like teeth. Eye small. Body naked or covered with minute spines; generally with tentacles. The spinous dorsal is reduced to three isolated spines, the anterior of which is modified into a tentacle, situated above the snout. The soft dorsal of moderate length; anal short. Ventrals present.

The fishes of this genus are pelagic, frequently met with in mid-ocean between the tropics, especially in parts of the sea with floating vegetation; not rarely individuals are found far from their native latitudes, carried by currents to the coasts of Norway and New Zealand. Their power of swimming is most imperfect. When near the coast they conceal themselves between corals, stones, or fucus, holding on to the ground by means of their arm-like pectoral fins. Their coloration is so similar to their surroundings that it is hardly possible to distinguish the fish from a stone or coral overgrown with vegetation. Their way of attracting and seizing their prey is evidently the same as in the other fishes of this family. The extraordinary range of some of the species which inhabit the Atlantic as well as the Indo-Pacific Oceans, is the consequence of their habit of attaching themselves to floating objects. Almost all the species are highly coloured, but the pattern of the various colours varies exceedingly. These fishes do not attain to any considerable size, and probably never exceed a length of ten inches. A great number of species have been distinguished by ichthyologists, but probably not more than twenty are known at present. The species figured on p. 295 (A. caudomaculatus) is common in the Red Sea, and probably occurs in other parts of the Indian Ocean.

Brachionichthys and Saccarius are allied genera from South Australia, Tasmania, and New Zealand.

Chaunax.—Head very large, depressed; cleft of the mouth wide, subvertical; eye small; rasp-like teeth in the jaws and palate. Skin covered with minute spines. The spinous dorsal is reduced to a small tentacle above the snout; the soft dorsal of moderate length; anal short; ventrals present.

A deep-sea fish (Ch. pictus), of uniform pink colour; hitherto found near Madeira and the Fidji Islands, at a depth of 215 fathoms.

Malthe.—Anterior portion of the body very broad and depressed. The anterior part of the snout is produced into a more or less prominent process, beneath which there is a tentacle retractile into a cavity. Jaws and palate with villiform teeth. Skin with numerous conical protuberances. Soft dorsal fin and anal very short. Gill-opening superiorly in the axil; gills two and a half.

Although the rostral tentacle is situated at the lower side of the projection of the snout, it must be regarded as the homologue of a dorsal spine. In some of the preceding genera, Oneirodes and Chaunax, the first dorsal spine is so far advanced on the snout as to come into connection with the intermaxillary processes; and the position of the rostral tentacle in Malthe is only a still more advanced step towards the same special purpose for which the first dorsal spine is used in this family, viz. for the purpose of obtaining food. In Malthe it is obviously an organ of touch. This genus belongs to the American shores of the Atlantic; M. vespertilio being a tropical, M. cubifrons a northern species.

Halieutæa.—Head exceedingly large, depressed, nearly circular in its circumference. Cleft of the mouth wide, horizontal. Jaws with small rasp-like teeth; palate smooth. Forehead with a transverse bony bridge, beneath which is a tentacle (rostral spine) retractile into a cavity. Body and head covered with small stellate spines. Soft dorsal and anal very short. Gill-opening superiorly in the axil; gills two and a half.

A coast-fish (H. stellata) from China and Japan. Frequently found dry in Chinese insect-boxes.

This genus appears to be represented in the Atlantic Ocean by Halieutichthys from Cuba, and by Dibranchus, dredged at a depth of 360 fathoms off the coast of West Africa; the latter genus possesses two gills only. Another genus, covered with large scattered tubercles, Aegæonichthys, has recently been described from New Zealand.

Thirteenth Family—Cottidæ.

Form of the body oblong, sub-cylindrical. Cleft of the mouth lateral. Dentition feeble, generally in villiform bands. Some bones of the head are armed; and a bony stay connects the præopercular spine with the infraorbital ring. Two dorsal fins (rarely one), the spinous being less developed than the soft and than the anal. Ventrals thoracic, with five or less soft rays.

The fishes of this family are of small size, bad swimmers, and generally living on the bottom, near the coasts, of almost all the arctic, temperate, and tropical seas. Only a few live in fresh water. They prefer shallow to deep water; and there is only one instance known of a member of this family living at a great depth, viz. Cottus bathybius from the Japanese sea, which is stated to have been dredged in a depth of 565 fathoms. Fossil representatives are few in number: two or three species of Trigla; others, although having a general resemblance to the genus Cottus, were covered with ctenoid scales, and therefore are referred to a distinct genus, Lepidocottus; they are from tertiary formations.

Cottus.—Head broad, depressed, rounded in front; body sub-cylindrical, compressed posteriorly. Scaleless; lateral line present. Pectoral rounded, with some or all the rays simple. Jaws and vomer with villiform teeth; palatine teeth none.

The “Bull-heads” or “Miller’s Thumbs” are small fishes from the shores and fresh waters of the northern temperate zone. Some forty species are known; the greater number live in the northern half of the temperate zone. On the shore, as well as in rivers, they prefer rocky or stony to muddy ground, lying concealed between the stones, and watching for their prey, which consists of small crustaceans and other aquatic animals. The common British Miller’s Thumb (C. gobio) is found in almost all suitable fresh waters of Northern and Central Europe, especially in small streams, and extends into Northern Asia. Other freshwater species abound in North America and Northern Asia. Cottus scorpius and C. bubalis, the common European marine species, range across the Atlantic to the American coasts. The male is said to construct a nest, for the reception of the spawn, of seaweeds and stones, and to anxiously watch and defend his offspring. The spine at the angle of the præoperculum, which is simple in the majority of the freshwater species, is frequently armed with accessory processes, and antler-like, in marine.

Cantridermichthys differs from Cottus in having teeth on the palatine bones.

Eleven species are known, distributed like Cottus, but absent in Europe and North-western Asia.

Icelus.—Head large, armed at the gill-covers and on the neck; body with a dorsal series of bony plates from the neck to the base of the caudal; lateral line with osseous tubercles; scattered scales on the sides and abdomen. Ventrals thoracic, with less than five rays. No pectoral filaments. Villiform teeth in the jaws, on the vomer and palatine bones.

Represents Cottus in the far north; I. hamatus is common in Spitzbergen and Greenland, and has been found in abundance in lat. 81° 44’.

Platycephalus.—Head broad, much depressed, more or less armed with spines; body depressed behind the head, sub-cylindrical towards the tail, covered with ctenoid scales. Two dorsal fins; the first spine isolated from the others. Ventrals thoracic, but rather remote from the base of the pectorals. Villiform teeth in the jaws, on the vomer and palatine bones.

Fig. 212.—Platycephalus cirrhonasus, from Port Jackson.

About forty species are known, of which some attain a length of two feet. This genus represents in the tropical Indian Ocean the Cotti of the Arctic, and the Nototheniæ of the Antarctic zone. Like these, they live on the bottom in shallow water, hidden in the sand, the colours of which are assimilated by those of their body. Therefore, they are very scarce near coral islands which are surrounded by great depths; whilst the number of species is rather considerable on many points of the shelving Australian coasts. Their long and strong ventral fins are of great use to them in locomotion. P. insidiator is one of the most common Indian and Australian fishes, and readily recognised by two oblique black bands on the upper and lower caudal lobes.

Fig. 213.—Scale from the lateral line of the same fish.

Hoplichthys, similar to Platycephalus, but with the back and sides of the body covered with bony spiny plates. No separate dorsal spine.

One species, H. langsdorffii, is common on the coast of Japan, and frequently placed dry by the Chinese into their insect-boxes.

Trigla.—Head parallelopiped, with the upper surface and the sides entirely bony, the enlarged infraorbital covering the cheek.

Two dorsal fins. Three free pectoral rays. Villiform teeth. Air-bladder generally with lateral muscles, often divided into two lateral halves. The species may be referred to three groups:—

1. Palatine teeth none; scales exceedingly small, except those of the lateral line: Trigla.

2. Palatine teeth none; scales of moderate size: Lepidotrigla.

3. Palatine teeth present: Prionotus.

Fig. 214.—Trigla pleuracanthica.

Fig. 215.—Scute of the lateral line of the same fish.

About forty species of “Gurnards” are known from tropical and temperate zones. They are too well known to need detailed description; one of their principal characteristics is the three free finger-like pectoral appendages, which serve as organs of locomotion as well as touch, and which are supplied with strong nerves, as noticed above (pp. 108 and 120). The fins are frequently beautifully ornamented, especially the inner side of the long and broad pectorals, which is most exposed to the light when the fish is floating on the surface of the water, with pectorals spread out like wings. The grunting noise made by Gurnards when taken out of the water is caused by the escape of gas from the air-bladder through the open pneumatic duct. Gurnards are generally used as food; seven species occur on the British coast: the Red Gurnard (T. pini), the Streaked Gurnard (T. lineata), the Sapphirine Gurnard (T. hirundo), the Grey Gurnard (T. gurnardus), Bloch’s Gurnard (T. cuculus), the Piper (T. lyra), and the Long-finned Gurnard (T. obscura or T. lucerna). Singularly, the European species cross the Atlantic but rarely, the American species belonging chiefly to the division Prionotus.

Several other genera belong to this family; for completeness’ sake they are mentioned here, viz. Bunocottus from Cape Horn; Rhamphocottus, Triglops from Arctic North America; Podabrus, Blepsias, Nautichthys, Scorpænichthys, Hemilepidotus, Artedius, from the North Pacific; Ptyonotus, from Lake Ontario; Polycaulus from Indian Seas; Bembras from the Japanese Sea.

Fourteenth Family—Cataphracti.

Form of the body elongate, sub-cylindrical. Dentition feeble. Body completely cuirassed with osseous keeled scales or plates. A bony stay connects the angle of the præoperculum with the infraorbital ring. Ventrals thoracic.

Marine fishes, and partly pelagic. Petalopteryx, from the chalk of Mount Lebanon, is supposed to have a resemblance to Dactylopterus.

Agonus.—Head and body angular, covered with bony plates. Two dorsal fins; no pectoral appendages. Small teeth in the jaws.

Small fishes, from the northern parts of the temperate zone and extending into the Arctic Ocean; the genus reappears in the Southern Hemisphere on the coast of Chile. Of the eleven species known, one (A. cataphractus) is not uncommon on the coast of Great Britain.

Aspidophoroides, from Greenland, has a very similar form of the body, but possesses one short dorsal fin only.

Siphagonus.—With the snout produced into a long tube like a Syngnathus; chin prominent, with a barbel.

From Behring’s Strait and Japan.

Peristethus.—Head parallelopiped, with the upper surface and the sides entirely bony; each præorbital prolonged into a long flat process, projecting beyond the snout. Body cuirassed with large bony plates. One continuous dorsal, or two dorsals, of which the second is the more developed. Two free pectoral appendages. Teeth none; lower jaw with barbels.

Singularly shaped fishes, of rather small size, from the Mediterranean, the warmer parts of the Atlantic, and the Indian Ocean; of the ten species known one species only has been found in the Pacific, near the Sandwich Islands. The European species is P. cataphractum. They are not common, and probably inhabit greater depths than the Gurnards, with which they have much in common as regards their habits.

Fig. 216.—Dactylopterus volitans.

Dactylopterus.—Head parallelopiped, with the upper surface and the sides entirely bony; scapula and angle of the præoperculum produced into long spines. Body with strongly keeled scales of moderate size; lateral line none. Two dorsal fins, the second not much longer than the first; pectoral very long, an organ of flying, with the upper portion detached and shorter. Granular teeth in the jaws; none on the palate. Air-bladder divided into two lateral halves, each with a larger muscle.

Of “Flying Gurnards” three species only are known, which are very abundant in the Mediterranean, the tropical Atlantic, and Indo-Pacific. They, and the Flying Herrings (Exocoetus), are the only fishes which are enabled by their long pectoral fins to take flying leaps out of the water, and deserve the name of “Flying-Fishes.” They are much heavier, and attain to a larger size, than the Exocoeti, specimens of eighteen inches in length not being scarce. When young, their pectorals are much shorter, and, consequently, they are unable to raise themselves out of the water (Cephalacanthus).

The vertebral column shows a singular coalescence of the anterior vertebræ, which form a simple tube, as in Fistularia.

---

We insert here as an appendix to this division the small family of Pegasidæ, the natural affinities of which are not yet clearly understood, but which resembles in some of its characters the Cataphracti.

Fifteenth Family—Pegasidæ.

Body entirely covered with bony plates, anchylosed on the trunk and movable on the tail. Barbels none. The margin of the upper jaw is formed by the intermaxillaries and their cutaneous prolongation, which extends downwards to the extremity of the maxillaries. Gill-cover formed by a large plate, homologous to the operculum, præoperculum, and sub-operculum; interoperculum a long fine bone, hidden below the gill-plate. One rudimentary branchiostegal. The gill-plate is united with the isthmus by a narrow membrane; gill-openings narrow, in front of the base of the pectoral fin. Gills four, lamellated. Pseudobranchiæ and air-bladder absent. One short dorsal and anal fin, opposite to each other. Ventral fin present. Ovarian sacs closed.

One genus only is known, Pegasus. Its pectoral fins are broad, horizontal, long, composed of simple rays, some of which are sometimes spinous. Ventral fins one- or two-rayed. Upper part of the snout produced into a shorter or longer process. Mouth inferior, toothless. Suborbital ring well developed, forming a suture with the gill-cover. Vertebræ in small number, thin; no ribs. Four species are known, two of which are of a shorter, and the two others of a longer form. The former are P. draconis, common in the Indian Ocean, and P. volans, which is frequently stuck by the Chinese into the insect-boxes which they manufacture for sale. The two elongate species, P. natans and P. lancifer, are from the Chinese and Australian coasts. They are all very small fishes, probably living on sandy shoal places near the coast.

Fig. 217.—Pegasus natans.

Ninth Division—Acanthopterygii Gobiiformes.

The spinous dorsal, or spinous portion of the dorsal is always present, short, either composed of flexible spines, or much less developed than the soft; the soft dorsal and anal of equal extent. No bony stay for the angle of the præoperculum. Ventrals thoracic or jugular, if present, composed of one spine and five, rarely four, soft rays. A prominent anal papilla.

Shore-fishes, mostly exclusively marine, but some entering and living in fresh waters.

First Family—Discoboli.

Body thick or oblong, naked or tubercular. Teeth small. Ventral fins with one spine and five rays, all being rudimentary and forming the osseous support of a round disk, which is surrounded by a cutaneous fringe. Gill-openings narrow, the gill-membranes being attached to the isthmus.

Carnivorous fishes, living at the bottom of the shores of northern seas. By their ventral disk they are enabled to attach themselves very firmly to rocks.

Cyclopterus.—Body thick, short, covered with a viscous, tubercular skin. Head large, snout short. Villiform teeth in the jaws, none on the palate. Skeleton soft, with but little earthy matter.

Fig. 218.—Cyclopterus lumpus. a, Ventral disk.

Three species of “Lump-suckers” are known from the northern temperate and the arctic zones. The common North European and North American species, C. lumpus, is known also by the names of “Cock- and Hen-Paddle.” It attains to a length of twenty-four inches, but generally is much smaller. It is difficult to remove it from any object to which it once has attached itself by means of its sucking-disk. Its skin is so thick as to more or less entirely conceal the first dorsal fin; it is covered with rough tubercles, the larger ones being arranged in four series along each side of the body. In young specimens these tubercles are absent. The arctic species, C. spinosus, has large conical plates on the head and body, each plate with a spine in the centre. Also of this species the young are naked, the plates making only gradually their appearance, in the form of groups of tubercles. Their development is irregular, as young specimens of the same size may be entirely naked or tubercular. This species ranges beyond the 81° lat. N.

Fig. 219.—Young of Cyclopterus spinosus, from the Arctic Ocean, natural size.

Liparis.—Body sub-cylindrical, enveloped in a more or less loose naked skin; head broad, obtuse. The infraorbital bone is styliform posteriorly, extending backwards to the margin of the præoperculum. One dorsal fin, with feeble flexible rays. Villiform teeth in the jaws, none on the palate.

Small fishes from the northern coasts of the temperate zone, ranging beyond the arctic circle. Eight species are known, of which two (L. lineatus and L. montagui) occur on the British coasts.

Second Family—Gobiidæ.

Body elongate, naked or scaly. Teeth generally small, sometimes with canines. The spinous dorsal fin, or portion of the dorsal fin, is the less developed, and composed of flexible spines; anal similarly developed as the soft dorsal. Sometimes the ventrals are united into a disk. Gill-opening more or less narrow, the gill-membranes being attached to the isthmus.

Small carnivorous littoral fishes, many of which have become acclimatised in fresh water. They are very abundant with regard to species as well as individuals, and found on or near the coasts of all temperate and tropical regions. Geologically they appear first in the chalk.

Gobius.—Body scaly. Two dorsal fins, the anterior generally with six flexible spines. Ventral fins united, forming a disk which is not attached to the abdomen. Gill-opening vertical, moderately wide.

Fig. 220.—Gobius lentiginosus, from New Zealand.

The “Gobies” are distributed over all temperate and tropical coasts, and abundant, especially on the latter. Nearly three hundred species have been described. They live especially on rocky coasts, attaching themselves firmly with their ventrals to a rock in almost any position, and thus withstanding the force of the waves. Many of the species seem to delight in darting from place to place in the rush of water which breaks upon the shore. Others live in quiet brackish water, and not a few have become entirely acclimatised in fresh water, especially lakes. The males of some species construct nests for the eggs, which they jealously watch, and defend even for some time after the young are hatched. Several species are found on the British coast: G. niger, paganellus, auratus, minutus, ruthensparri. Fossil species of this genus have been found at Monte Bolca.

A very small Goby, Latrunculus pellucidus, common in some localities of the British Islands and other parts of Europe, is distinguished by its transparent body, wide mouth, and uniserial dentition. According to R. Collett it offers some very remarkable peculiarities. It lives one year only, being the first instance of an annual vertebrate. It spawns in June and July, the eggs are hatched in August, and the fishes attain their full growth in the months from October to December. In this stage the sexes are quite alike, both having very small teeth and feeble jaws. In April the males lose the small teeth, which are replaced by very long and strong teeth, the jaws themselves becoming stronger. The teeth of the females remain unchanged. In July and August all the adults die off, and in September only the fry are to be found.

There are several other genera, closely allied to Gobius, as Euctenogobius, Lophiogobius, Doliichthys, Apocryptes, Evorthodus, Gobiosoma and Gobiodon (with scaleless body) Triænophorichthys.

Sicydium.—Body covered with ctenoid scales of rather small size. Cleft of the mouth nearly horizontal, with the upper jaw prominent; lips very thick; the lower lip generally with a series of minute horny teeth. A series of numerous small teeth in upper jaw, implanted in the gum, and generally movable; the lower jaw with a series of conical widely-set teeth. Two dorsal fins, the anterior with six flexible spines. Ventral fins united, and forming a short disk, more or less adherent to the abdomen.

Small freshwater fishes inhabiting the rivers and rivulets of the islands of the tropical Indo-Pacific. About twelve species are known; one occurs in the West Indies. Lentipes from the Sandwich Islands is allied to Sicydium.

Periophthalmus.—Body covered with ctenoid scales of small or moderate size. Cleft of the mouth nearly horizontal, with the upper jaw somewhat longer. Eyes very close together, immediately below the upper profile, prominent, but retractile, with a well-developed outer eyelid. Teeth conical, vertical in both jaws. Two dorsal fins, the anterior with flexible spines; caudal fin with the lower margin oblique; base of the pectoral fin free, with strong muscles. Ventral fins more or less coalesced. Gill-openings narrow.

The fishes of this genus, and the closely-allied Boleophthalmus, are exceedingly common on the coasts of the tropical Indo-Pacific, especially on parts covered with mud or fucus. During ebb they leave the water and hunt for small crustaceans, and other small animals disporting themselves on the ground which is left uncovered by the receding water. With the aid of their strong pectoral and ventral fins and their tail, they hop freely over the ground, and escape danger by rapid leaps. The peculiar construction of their eyes, which are very movable, and can be thrust far out of their sockets, enables them to see in the air as well as in the water; when the eyes are retracted they are protected by a membranous eyelid. These fishes are absent in the eastern parts of the Pacific and on the American side of the Atlantic; but singularly enough one species reappears on the West African coast. About seven species are known (including Boleophthalmus), P. koelreuteri being one of the most common fishes of the Indian Ocean.

Fig. 221.—Periophthalmus koelreuteri.

Eleotris.—Body scaly; eyes of moderate size, lateral, not prominent. Teeth small. Two dorsal fins, the anterior generally with six spines. Ventrals not united, though close together, with one spine and five rays.

About sixty species are known from the tropics, only a few extending into the temperate zone. As regards form, they repeat almost all the modifications observed among the Gobies, from which they differ only in having the ventral fins non-coalescent. On the whole they are somewhat larger than the Gobies, and rather freshwater than marine species, some of them being abundant in the rivulets of the islands of the Indo-Pacific and Atlantic. Others have even penetrated into the inland-waters of the African continent.

Trypauchen.—Body elongate, covered with minute scales; head compressed, with a deep cavity on each side, above the operculum. Teeth small, in a band. One dorsal, the spinous portion composed of six spines; dorsal and anal fins continuous with the caudal, ventral fins united.

Small fishes of singular aspect, from the East Indian coasts. Three species, of which T. vagina is common.

Callionymus.—Head and anterior part of the body depressed, the rest cylindrical, naked. Snout pointed, with the cleft of the mouth narrow, horizontal, and with the upper jaw very protractile. Eyes rather large, more or less directed upwards. Teeth very small, palate smooth. A strong spine at the angle of the præoperculum. Two dorsal fins, the anterior with three or four flexible spines; ventrals five-rayed, widely apart from each other. Gill-openings very narrow, generally reduced to a foramen on the upper side of the operculum.

The “Dragonets” are small, and generally beautifully coloured marine fishes, inhabitants of the coasts of the temperate zone of the Old World; the minority of species live in tropical parts of the Indo-Pacific; and these seem to descend to somewhat greater depths than the littoral species of the northern hemisphere. Secondary sexual characters are developed in almost all the species, the mature males having the fin-rays prolonged into filaments, and the fin-membranes brightly ornamented. On the British coast one species (C. draco) is very common, and locally called “Skulpin.” About thirty species are known, many of which have the præopercular spine armed with processes or barbs. Vulsus is allied to Callionymus.

Other genera belonging to this family are—Benthophilus from the Caspian Sea; Amblyopus, Orthostomus, Platyptera, Luciogobius, Oxymetopon, and, perhaps, Oxuderces.

Tenth Division—Acanthopterygii Blenniiformes.

Body low, sub-cylindrical or compressed, elongate. Dorsal fin very long; the spinous portion of the dorsal, if distinct, is very long, as well developed, as the soft, or much more; sometimes the entire fin is composed of spines only; anal more or less long; caudal fin subtruncated or rounded, if present. Ventral fins thoracic or jugular, if present.

First Family—Cepolidæ.

Body very elongate, compressed, covered with very small cycloid scales; eyes rather large, lateral. Teeth of moderate size. No bony stay for the angle of the præoperculum. One very long dorsal fin, which, like the anal, is composed of soft rays. Ventrals thoracic, composed of one spine and five rays. Gill-opening wide. Caudal vertebræ exceedingly numerous.

The “Band-fishes” (Cepola) are small marine fishes, belonging principally to the fauna of the northern temperate zone; in the Indian Ocean the genus extends southwards to Pinang. The European species (C. rubescens) is found in isolated examples on the British coast, but is less scarce in some years than in others. These fishes are of a nearly uniform red colour.

Second Family—Trichonotidæ.

Body elongate, sub-cylindrical, covered with cycloid scales of moderate size. Eyes directed upwards. Teeth in villiform bands. No bony stay for the angle of the præoperculum. One long dorsal fin, with simple articulated rays, and without a spinous portion; anal long. Ventrals jugular, with one spine and five rays. Gill-opening very wide. The number of caudal vertebræ much exceeding that of the abdominal.

Small marine fishes, belonging to two genera only, Trichonotus (setigerus) from Indian Seas, with some of the anterior dorsal rays prolonged into filaments; and Hemerocoetes (acanthorhynchus) from New Zealand, and sometimes found far out at sea on the surface.

Third Family—Heterolepidotidæ.

Body oblong, compressed, scaly; eyes lateral; cleft of the mouth lateral; dentition feeble. The angle of the præoperculum connected by a bony stay with the infraorbital ring. Dorsal long, with the spinous and soft portions equally developed; anal elongate. Ventrals thoracic, with one spine and five rays.

Fig. 222.—Scale from the lateral line of Hemerocœtes acanthorhynchus, with lacerated margin.

Fig. 223.—Chirus hexagrammus, from Japan.

Small shore-fishes, characteristic of the fauna of the Northern Pacific, some of the species occurring on the American as well as Asiatic side. They have been referred to several genera, as

Chirus, which is distinguished by the presence of several lateral lines;

Ophiodon, with one lateral line only, cycloid scales, and slightly armed præoperculum;

Agrammus, with one lateral line only, ctenoid scales, and unarmed præoperculum; and

Zaniolepis, with one lateral line and minute comb-like scales.

Fourth Family—Blenniidæ.

Body elongate, low, more or less cylindrical, naked or covered with scales, which generally are small. One, two, or three dorsal fins occupying nearly the whole length of the back, the spinous portion, if distinct, being as much developed as the soft, or more; sometimes the entire fin is composed of spines; anal fin long. Ventrals jugular, composed of a few rays, and sometimes rudimentary or entirely absent. Pseudobranchiæ generally present.

Littoral forms of great generic variety, occurring abundantly in all temperate and tropical seas. Some of the species have become acclimatised in fresh water, and many inhabit brackish water. With very few exceptions they are very small, some of the smallest fishes belonging to the family of “Blennies.” One of the principal characteristics of the Blennies is the ventral fin, which is formed by less than five rays, and has a jugular position. The Blennies have this in common with many Gadoids, and it is sometimes difficult to decide to which of these two families a fish should be referred. In such doubtful cases the presence of the pseudobranchiæ (which are absent in Gadoids) may be of assistance.

In many Blennies the ventral fins have ceased to have any function, and become rudimentary, or are even entirely absent. In others the ventral fins, although reduced to cylindrical stylets, possess a distinct function, and are used as organs of locomotion, by the aid of which the fish moves rapidly over the bottom.

The fossil forms are scarcely known; Pterygocephalus from Monte Bolca appears to have been a Blennioid.

Anarrhichas.—Body elongate, with rudimentary scales; snout rather short; cleft of the mouth wide; strong conical teeth in the jaws, those on the sides with several pointed tubercles; a biserial band of large molar teeth on the palate. Dorsal fin long, with flexible spines; caudal separate. Ventrals none. Gill-openings wide.

The “Sea-wolf,” or “Sea-cat” (A. lupus), is a gigantic Blenny, attaining to a length of more than six feet. With its enormously strong tubercular teeth it is able to crush the hardest shells of Crustaceans or Mollusks, on which it feeds voraciously. It is an inhabitant of the northern seas, like two other allied species, all of which are esteemed as food by the inhabitants of Iceland and Greenland. Two other species of Sea-wolves occur in the corresponding latitudes of the North Pacific.

Fig. 224.—Teeth of the Wolf-fish, Anarrhichas lupus.

Blennius.—Body moderately elongate, naked; snout short. A single dorsal, without detached portion; ventrals jugular, formed by a spine and two rays. Cleft of the mouth narrow; a single series of immovable teeth in the jaws; generally a curved tooth behind this series in both jaws, or in the lower only. A more or less developed tentacle above the orbit. Gill-opening wide.

About forty species of Blennius (in the restricted generic sense) are known from the northern temperate zone, the tropical Atlantic, Tasmania, and the Red Sea. But in the tropical Indian Ocean they are almost entirely absent, and replaced by other allied genera. Three species, found near the Sandwich Islands, are immigrants into the Pacific from the American Continent. They generally live on the coast, or attach themselves to floating objects, some species leading a pelagic life, hiding themselves in floating seaweed, in which they even propagate their species. All species readily accustom themselves to fresh water, and some (B. vulgaris) have become entirely acclimatised in inland lakes. British species are B. gattorugine (growing to a length of twelve inches), B. ocellaris, B. galerita, and B. pholis, the common “Shanny.”

Chasmodes is a genus allied to Blennius, from the Atlantic coasts of temperate North America.

Fig. 225.—Petroscirtes bankieri, from Hong-Kong.

Petroscirtes.—Body moderately elongate, naked. Snout generally short. A single dorsal fin; ventrals composed of two or three rays. Cleft of the mouth narrow; a single series of immovable teeth in the jaws; a strong curved canine tooth behind this series, that of the lower jaw much stronger than that of the upper. Head sometimes with tentacles. Gill-opening reduced to a small fissure above the root of the pectoral.

Thirty species, from the tropical Indo-Pacific, of small size.

Fig. 226.—Dentition of the same, enlarged.

Salarias.—Body moderately elongate, naked; snout short, with transverse cleft of the mouth; a series of numerous small teeth in the jaws, implanted in the gum and movable; generally a curved canine tooth on each side of the lower jaw, behind the series of small teeth. Dorsal fin continuous, sometimes divided into two portions by a more or less deep notch without a detached anterior part. Ventral fins with two or three rays. A tentacle above the orbit. Gill-openings wide.

Sixty species are known from the tropical zone, extending northwards to Madeira, southwards to Chile and Tasmania. In certain individuals of some of the species a longitudinal cutaneous crest is developed; all young individuals lack it, and in some other species it is invariably absent. Singularly enough this crest is not always a sexual character, as one might have supposed from analogy, but in some species at least it is developed in both sexes. Mature males, however, have generally higher dorsal fins and a more intense and variegated coloration than females and immature males, as is also the case in Blennius.

Clinus.—Body moderately elongate, covered with small scales; snout rather short; a narrow band or series of small teeth in the jaws and on the palate. Dorsal fin formed by numerous spines and a few soft rays, without a detached anterior portion; anal spines two. Ventrals with two or three rays. A tentacle above the orbit. Gill-opening wide.

Thirty species, from the coasts of tropical America and the southern temperate zone. Three other genera are closely allied to Clinus, viz. Cristiceps and Cremnobates, in which the three anterior dorsal spines are detached from the rest of the fin; and Tripterygium, with three distinct dorsal fins, of which the two anterior are spinous. The species of these genera are as numerous as those of Clinus, occurring in many parts of tropical seas, in the Mediterranean, and being especially well represented in South Australia and New Zealand.

Stichæus.—Body elongate, covered with very small scales; lateral line more or less distinct, sometimes several lateral lines. Snout short; very small teeth in the jaws, and generally on the palate. Dorsal fin long, formed by spines only. Ventrals with two or three rays. Caudal fin distinct. Gill-openings rather wide.

Small fishes, peculiar to the coasts near the arctic circle, ranging southwards to the coasts of Japan and Scandinavia. Ten species.

Blenniops.—Body moderately elongate, covered with very small scales; lateral line none. Snout short; small teeth in the jaws, none on the palate. Dorsal fin long, formed by spines only. Ventrals with one spine and three rays. Caudal distinct. Gill-openings of moderate width, the gill-membranes coalescent across the isthmus.

A fine but not common kind of Blenny (B. ascanii), from the British and Scandinavian coasts.

Centronotus.—Body elongate, covered with very small scales; lateral line none. Snout short; very small teeth in the jaws. Dorsal fin long, formed by spines only. Ventrals none or rudimentary; caudal separate. Gill-openings of moderate width, gill-membranes coalescent.

Ten species are known from the northern coasts; southwards the genus extends to the coasts of France, New York, California, and Japan. C. gunellus, or the “Gunnel-fish” or “Butter-fish,” is common on the British coasts. Apodichthys is allied to Centronotus, but the vertical fins are confluent; and a very large, excavated, pen-like spine lies hidden in a pouch in front of the anal fin. This spine is evidently connected in some way with the generative organs, as a furrow leads from the orifice of the oviduct to the groove of the spine. One species from the Pacific coast of North America. Xiphidion is another closely allied genus from the same locality.

Cryptacanthodes.—Body very elongate, naked, with a single lateral line. Head with the muciferous system well developed. Eye rather small. Conical teeth in the jaws, on the vomer and palatine bones. One dorsal formed by spines only; caudal connected with dorsal and anal. Ventrals none. Gill-opening of moderate width, with the gill-membranes joined to the isthmus.

One species (C. maculatus) from the Atlantic coasts of North America.

Patæcus.—Body oblong, elevated anteriorly; snout short, with subvertical anterior profile; minute teeth in the jaws and on the vomer. Dorsal fin with the anterior spines strong and long, continuous with the caudal; ventrals none. Gill-openings wide.

Fig. 227.—Patæcus fronto.

Three species of this singular form are known from South and West Australia.

Zoarces.—Body elongate, with the scales rudimentary; conical teeth in the jaws. Dorsal fin long, with a depression on the tail, which is formed by a series of spines much shorter than the rays. No other fin-spines. No separate caudal fin. Ventrals short, formed by three or four rays. Gill-openings wide.

Two species are known, one from the European, and the other from the North American side of the Atlantic. The former, Z. viviparus, is well known by the name of “Viviparous Blenny;” as is signified by this name it produces its young alive. These are so matured at the time of their birth that on their first exclusion they swim about with the utmost agility. No fewer than from two to three hundred young are sometimes produced by one female, and the abdomen of the mother is so distended before parturition that it is impossible to touch it without causing them to be extruded. Full grown individuals are about twelve inches long, but the American species (Z. anguillaris) attains to a length of two or three feet.

Other genera of the family of Blennoids are:—Blennophis, Nemophis, Plagiotremus, Neoclinus, Cebidichthys, Myxodes, Heterostichus, Dictyosoma, Lepidoblennius, Dactyloscopus, Gunellichthys, Urocentrus, Stichæopsis, Sticharium, Notograptus, Pholidichthys, and Pseudoblennius.

Fifth Family—Acanthoclinidæ.

Body elongate, low, compressed, covered with small scales. One dorsal fin, occupying nearly the whole of the back, and chiefly composed of spines. Anal fin long, with numerous spines. Ventrals jugular, composed of a few rays only.

Of this family one fish only is known (Acanthoclinus littoreus), a small Blenny abundant on the coast of New Zealand.

Sixth Family—Mastacembelidæ.

Body elongate, eel-like, covered with very small scales. Mandible long, but little moveable. Dorsal fin very long, the anterior portion composed of numerous short isolated spines; anal fin with spines anteriorly. Ventrals none. The humeral arch is not suspended from the skull. Gill-openings reduced to a slit at the lower part of the side of the head.

Freshwater-fishes characteristic of and almost confined to the Indian region. The structure of the mouth and of the branchial apparatus, the separation of the humeral arch from the skull, the absence of ventral fins, the anatomy of the abdominal organs, affords ample proof that these fishes are Acanthopterygian eels. Their upper jaw terminates in a pointed moveable appendage, which is concave and transversely striated inferiorly in Rhynchobdella, and without transverse striæ in Mastacembelus: the only two genera of this family. Thirteen species are known, of which Rh. aculeata, M. pancalus and M. armatus are extremely common, the latter attaining to a length of two feet. Outlying species are M. aleppensis from Mesopotamia and Syria, and M. cryptacanthus, M. marchei, and M. niger, from West Africa.

Fig. 228.—Mastacembelus argus, from Siam.

Eleventh Division—Acanthopterygii Mugiliformes.

Two dorsal fins more or less remote from each other; the anterior either short, like the posterior, or composed of feeble spines. Ventral fins with one spine and five rays, abdominal.

First Family—Sphyrænidæ.

Body elongate, sub-cylindrical, covered with small cycloid scales; lateral line continuous. Cleft of the mouth wide, armed with strong teeth. Eye lateral, of moderate size. Vertebræ twenty-four.

This family consists of one genus only, Sphyræna, generally called “Barracudas,” large voracious fishes from the tropical and sub-tropical seas, which prefer the vicinity of the coast to the open sea. They attain to a length of eight feet, and a weight of forty pounds; individuals of this large size are dangerous to bathers. They are generally used as food, but sometimes (especially in the West Indies) their flesh assumes poisonous qualities, from having fed on smaller poisonous fishes. Seventeen species.

The Barracudas existed in the tertiary epoch, their remains being frequently found at Monte Bolca. Some other fossil genera have been associated with them, but as they are known from jaws and teeth or vertebræ only, their position in the system cannot be exactly determined; thus Sphyrænodus and Hypsodon from the chalk of Lewes, and the London clay of Sheppey. The American Portheus is allied to Hypsodon. Another remarkable genus from the chalk, Saurocephalus, has been also referred to this family.[44]

Second Family—Atherinidæ.

Body more or less elongate, sub-cylindrical, covered with scales of moderate size; lateral line indistinct. Cleft of the mouth of moderate width, with the dentition feeble. Eye lateral, large or of moderate size. Gill-openings wide. Vertebræ very numerous.

Small carnivorous fishes inhabiting the seas of the temperate and tropical zones; many enter fresh water, and some have been entirely acclimatised in it. This family seems to have been represented in the Monte Bolca formation by Mesogaster.

Atherina.—Teeth very small; scales cycloid. The first dorsal is short and entirely separated from the second. Snout obtuse, with the cleft of the mouth straight, oblique, extending to or beyond the anterior margin of the eye.

The Atherines are littoral fishes, living in large shoals, which habit has been retained by the species acclimatised in fresh water. They rarely exceed a length of six inches, but are nevertheless esteemed as food. From their general resemblance to the real Smelt they are often thus misnamed, but may always be readily recognised by their small first spinous dorsal fin. The young, for some time after they are hatched, cling together in dense masses, and in numbers almost incredible. The inhabitants of the Mediterranean coast of France call these newly hatched Atherines “Nonnat” (unborn). Some thirty species are known, of which A. presbyter and A. boyeri occur on the British coast.

Atherinichthys, distinguished from Atherina in having the snout more or less produced; and the cleft of the mouth generally does not extend to the orbit.

These Atherines are especially abundant on the coasts and in the fresh waters of Australia and South America. Of the twenty species known, several attain a length of eighteen inches and a weight of more than a pound. All are highly esteemed as food; but the most celebrated is the “Pesce Rey” of Chile (A. laticlavia).

Tetragonurus.—Body rather elongate, covered with strongly keeled and striated scales. The first dorsal fin is composed of numerous feeble spines, and continued on to the second. Lower jaw elevated, with convex dental margin, and armed with compressed, triangular, rather small teeth, in a single series.

This very remarkable fish is more frequently met with in the Mediterranean than in the Atlantic, but generally scarce. Nothing is known of its habits; when young it is one of the fishes which accompany Medusæ, and, therefore, it must be regarded as a pelagic form. Probably, at a later period of its life, it descends to greater depths, coming to the surface at night only. It grows to a length of eighteen inches.

Third Family—Mugilidæ.

Body more or less oblong and compressed, covered with cycloid scales of moderate size; lateral line none. Cleft of the mouth narrow or of moderate width, without or with feeble teeth. Eye lateral, of moderate size. Gill-opening wide. The anterior dorsal fin composed of four stiff spines. Vertebræ twenty-four.

The “Grey Mullets” inhabit in numerous species and in great numbers the coasts of the temperate and tropical zones. They frequent brackish waters, in which they find an abundance of food which consists chiefly of the organic substances mixed with mud or sand; in order to prevent larger bodies from passing into the stomach, or substances from passing through the gill-openings, these fishes have the organs of the pharynx modified into a filtering apparatus. They take in a quantity of sand or mud, and, after having worked it for some time between the pharyngeal bones, they eject the roughest and indigestible portion of it. The upper pharyngeals have a rather irregular form; they are slightly arched, the convexity being directed towards the pharyngeal cavity, tapering anteriorly and broad posteriorly. They are coated with a thick soft membrane, which reaches far beyond the margin of the bone, at least on its interior posterior portion; this membrane is studded all over with minute horny cilia. The pharyngeal bone rests upon a large fatty mass, giving it a considerable degree of elasticity. There is a very large venous sinus between the anterior portion of the pharyngeal and the basal portion of the branchial arches. Another mass of fat, of elliptical form, occupies the middle of the roof of the pharynx, between the two pharyngeal bones. Each branchial arch is provided on each side, in its whole length, with a series of closely-set gill-rakers, which are laterally bent downwards, each series closely fitting into the series of the adjoining arch; they constitute together a sieve, admirably adapted to permit a transit for the water, retaining at the same time every other substance in the cavity of the pharynx.

The lower pharyngeal bones are elongate, crescent-shaped, and broader posteriorly than anteriorly. Their inner surface is concave, corresponding to the convexity of the upper pharyngeals, and provided with a single series of lamellæ, similar to those of the branchial arches, but reaching across the bone from one margin to the other.

The intestinal tract shows no less peculiarities. The lower portion of the œsophagus is provided with numerous long thread-like papillæ, and continued into the oblong-ovoid membranaceous cœcal portion of the stomach, the mucosa of which forms several longitudinal folds. The second portion of the stomach reminds one of the stomach of birds; it communicates laterally with the other portion, is globular, and surrounded by an exceedingly strong muscle. This muscle is not divided into two as in birds, but of great thickness in the whole circumference of the stomach, all the muscular fasciculi being circularly arranged. The internal cavity of this stomach is rather small, and coated with a tough epithelium, longitudinal folds running from the entrance opening to the pyloric, which is situated opposite to the other. A low circular valve forms a pylorus. There are five rather short pyloric appendages. The intestines make a great number of circumvolutions, and are seven feet long in a specimen thirteen inches in length.

Fig. 229.—Mugil proboscideus.

Some seventy species of Grey Mullets are known, the majority of which attain to a weight of about four pounds, but there are many which grow to ten and twelve pounds. All are eaten, and some even esteemed, especially when taken out of fresh water. If attention were paid to their cultivation, great profits could be made by fry being transferred into suitable backwaters on the shore, in which they rapidly grow to a marketable size. Several species are more or less abundant on the British coasts, as Mugil octo-radiatus (Fig. [105], p. 254), M. capito, M. auratus (Fig. [106], p. 254), and M. septentrionalis (Fig. [107], p. 254), which, with the aid of the accompanying figures, and by counting the rays of the anal fin, may be readily distinguished—M. octo-radiatus having eight, and M. capito and M. auratus nine soft rays. A species inhabiting fresh waters of Central America (M. proboscideus) has the snout pointed and fleshy, thus approaching certain other freshwater and littoral Mullets, which, on account of a modification of the structure of the mouth, have been formed into a distinct genus, Agonostoma. Myxus comprises Mullets with teeth more distinct than in the typical species.

This genus existed in the tertiary epoch, remains of a species having been found in the gypsum of Aix, in Provence.

Twelfth Division—Acanthopterygii Gastrosteiformes.

The spinous dorsal is composed of isolated spines if present; the ventrals are either thoracic or have an abdominal position in consequence of the prolongation of the pubic bones which are attached to the humeral arch. Mouth small, at the end of the snout which is generally more or less produced.

First Family—Gastrosteidæ.

Body elongate, compressed. Cleft of the mouth oblique; villiform teeth in the jaws. Opercular bones not armed; infraorbitals covering the cheek; parts of the skeleton forming incomplete external mails. Scales none, but generally large scutes along the side. Isolated spines in front of the soft dorsal fin. Ventral fins abdominal, joined to the pubic bone, composed of a spine and a small ray. Branchiostegals three.

Fig. 230.—Gastrosteus noveboracensis.

Of “Sticklebacks” (Gastrosteus) about ten species are satisfactorily known, one of which (G. spinachia) lives in salt and brackish water, whilst the others inhabit principally fresh waters, although they all are able to exist in the sea. They are confined to the Temperate and Arctic zones of the northern hemisphere. The British freshwater species are the Three-spined Stickleback (G. aculeatus), which sometimes, especially in Central Europe, lacks scutes, sometimes has a series of scutes along the side of the body; the Four-spined Stickleback (G. spinulosus) and the Nine-spined Stickleback (G. pungitius). The commonest North American species is G. noveboracensis. The habits of all the freshwater species are very similar. The common European species (G. aculeatus) is an active and greedy little fish, extremely destructive to the fry of other species, and consequently injurious in ponds where these are sought to be preserved. It is scarcely to be conceived what damage these little fishes do, and how greatly detrimental they are to the increase of all the fishes in general among which they live; for it is with the utmost industry, sagacity, and greediness that they seek out and destroy all the young fry that come their way. A small Stickleback, kept in an aquarium, devoured, in five hours’ time, seventy-four young dace, which were about a quarter of an inch long, and of the thickness of a horse hair. Two days after it swallowed sixty-two; and would, probably, have eaten as many every day could they have been procured. The Stickleback sometimes swarms in prodigious numbers. Pennant states that at Spalding, in Lincolnshire, there was once in seven years amazing shoals, which appear in the Welland, coming up the river in the form of a vast column. The quantity may, perhaps, be conceived from the fact that a man employed in collecting them, gained, for a considerable time, four shillings a-day by selling them at the rate of a halfpenny a bushel. Costa, who studied the manners of these small fishes, relates that, on the approach of spawning time, the male builds a nest of stalks of grass and other matters in a hollow of the bottom, a little above three inches wide and about six inches and a half deep, creeping over the materials on his belly, and cementing them with the mucus that exudes from his skin. The bottom of the nest is first laid, then the sides are raised, and lastly the top is covered over. A small hole is left on one side for an entrance. When the erection is complete, he seeks out a female, and conducting her, Costa says, with many caresses, to the nest, introduces her by the door into the chamber. In a few minutes she has laid two or three eggs, after which she bores a hole on the opposite side of the nest to that by which she entered, and makes her escape. The nest has now two doors, and the eggs are exposed to the cool stream of water, which, entering by one door flows out at the other. Next day the male goes again in quest of a female, and sometimes brings back the same, sometimes finds a new mate. This is repeated until the nest contains a considerable number of eggs, and each time the male rubs his side against the female and passes over the eggs. Next the male watches a whole month over his treasure, defending it stoutly against all invaders, and especially against his wives, who have a great desire to get at the eggs. When the young are hatched and able to do for themselves his cares cease.

The Sea-Stickleback (G. spinachia) is likewise a nest builder, choosing for its operations especially the shallows of brackish water, which are covered with Zostera.

Second Family—Fistulariidæ.

Fishes of greatly elongated form; the anterior bones of the skull are much produced, and form a long tube, terminating in a narrow mouth. Teeth small; scales none, or small. The spinous dorsal fin is either formed by feeble isolated spines or entirely absent; the soft dorsal and anal of moderate length, ventral fins thoracic or abdominal, composed of five or six rays, without spine; if abdominal, they are separate from the pubic bones, which remain attached to the humeral arch. Branchiostegals five.

The “Flute-mouths” are also frequently called “Pipe-fishes,” a name which they have in common with the Syngnathidæ. They are gigantic marine Sticklebacks, living near the shore, from which they are frequently driven into the open sea; some of the species, therefore, have a wide geographical range. Probably all enter brackish water. They are distributed over the whole of the tropical and sub-tropical parts of the Atlantic and Indo-Pacific. The species are few in number, but some of them are very common.

This family is well represented in Eocene formations; some of the remains belonging to the existing genera, Fistularia, Aulostoma, and Auliscops, the two former of which occur not rarely at Monte Bolca and in the schists of Glaris. Well-preserved remains of Auliscops have been found in the Marl-slates of the highlands of Padang in Sumatra. Extinct genera from Monte Bolca are Urosphen, the cylindrical body of which is terminated by a large cuneiform fin; and Rhamphosus, which has an immense spinous ray, denticulated behind, inserted on the nape.

Fistularia.—Body scaleless; caudal fin forked, with the two middle rays produced into a filament; no free dorsal spines.

Three species are known, common on the shores of the Tropical Atlantic (F. tabaccaria) and Indian Oceans (F. serrata and F. depressa); they attain to a length of from four to six feet.

The anterior portion of the vertebral column shows the same peculiarity as in Dactylopterus; it is a long compressed tube, composed of four elongate vertebræ, which are perfectly anchylosed; each of them has a pair of small foramina for blood-vessels. The neural spines and parapophyses of this tubiform portion are confluent into thin laminæ, the lateral of which are wing-like, and expanded in their anterior half.

Aulostoma.—Body covered with small scales. Caudal fin rhombic, without prolonged rays; a series of isolated feeble dorsal spines. Teeth rudimentary.

Two species from the Tropical Atlantic and Indian Oceans.

Auliscops.—Body naked. Ventrals thoracic. Numerous spines in front of the dorsal fin.

One species (A. spinescens) from the Pacific coast of North America. Aulorhynchus from the same sea, and Aulichthys from Japan, are allied genera.

Thirteenth Division—Acanthopterygii Centrisciformes.

Two dorsal fins; the spinous short, the soft and the anal of moderate extent. Ventral fins truly abdominal, imperfectly developed.

This division consists of one family, Centriscidæ, with two genera. The fishes belonging to it are very small, marine, and, in consequence of their limited power of swimming, often driven out into the open sea. They have the same structure of the mouth and snout as the Fistulariidæ, but combine with it peculiarities of the shape of body, of the structure of the vertical fins, and of the relations between endo- and exo-skeleton, which render them altogether a singular and interesting type. Amphisile has been found in a fossil state at Monte Bolca.

Centriscus.—Body oblong or elevated, compressed, covered with small rough scales; lateral line none; some bony strips on the side of the back, and on the margin of the thorax and abdomen; the former, in one species, are confluent and form a shield. Teeth none. Two dorsal fins, the first with one of the spines very strong. Ventral fins small, abdominal, composed of five soft rays. Four branchiostegals.

Fig. 231.—Centriscus humerosus.

Of the four species the most generally known is C. scolopax, the “Trumpet-fish” or “Bellows-fish,” which rarely occurs on the south coast of England, is more common farther south, and reappears in Tasmania. The allied C. gracilis is one of the fishes common to the Mediterranean and Japanese Seas. The species figured, C. humerosus, occurs on the coast of South Australia, and is very scarce.

Amphisile.—Body elongate, strongly compressed, provided with a dorsal cuirass, which is formed by portions of the skeleton; the longitudinal axis of the tail is not in the same line with that of the trunk. Scales none. Teeth none. Two dorsal fins situated on the hindmost part of the back; ventral fins rudimentary, abdominal. Three or four branchiostegals.

The three species known of this genus are found in the tropical Indo-Pacific. Their body is so thin that it has the appearance of being artificially compressed between two sheets of paper; it is semi-transparent, especially in the region of the air-bladder. The structure of the vertebral column is extremely singular and unique among Acanthopterygians. The abdominal portion is more than four times as long as the caudal; nevertheless it is composed of only six vertebræ, whilst the latter consists of fourteen. The abdominal vertebræ are extremely slender, the third alone being nearly as long as the whole caudal portion; they have a slight ridge superiorly and inferiorly, and on each side; the whole portion lying in the uppermost concavity of the dorsal cuirass. The caudal vertebræ are extremely short, and the strength of their neural and hæmal spines is in proportion to their size. The dorsal cuirass is not a dermal production, but formed by modified parts of the endoskeleton; its composition, the number and condition of its single parts, and, finally, the first dorsal spine, which in A. punctulata is so singularly attached to it, favour this opinion. The plates, which occupy the vertebral line, would correspond to the neural spines, and the lateral plates on which the ribs are suspended to the parapophyses. Amphisile may be considered as a Chelonian form among fishes.

Fourteenth Division—Acanthopterygii Gobiesociformes.

No spinous dorsal; the soft and the anal short or of moderate length, situated on the tail; ventral fins subjugular, with an adhesive apparatus between them. Body naked.

These fishes are well characterised by their single dorsal fin, and by their adhesive ventral apparatus, which has only an external similarity to the organ observed in Cyclopterus and Liparis; its structure is typically different from it. Whilst in those genera the ventral fins occupy the centre of the disk forming its base, these fins are here widely apart from each other, as in Callionymus, forming only a portion of the periphery of the disk, which is completed by a cartilaginous expansion of the coracoid bones. The following description of its structure is taken from Sicyases sanguineus, but it is essentially the same in all the genera.

The whole disk is exceedingly large, subcircular, longer than broad, its length being one-third of the whole length of the fish. The central portion is formed merely by skin, which is separated from the pelvic or pubic bones by several layers of muscles. The peripheric portion is divided into an anterior and posterior part by a deep notch behind the ventrals. The anterior peripheric portion is formed by the four ventral rays, the membrane between them, and a broad fringe which extends anteriorly from one ventral to the other; this fringe is a fold of the skin, containing on each side the rudimentary ventral spine, but no cartilage. The posterior peripheric portion is suspended on each side from the coracoid, the upper bone of which is exceedingly broad, becoming a free movable plate behind the pectoral. A broad cartilage is firmly attached to it. The lower bone of the coracoid is of a triangular form, and supports a very broad fold of the skin, extending from one side to the other, and containing a cartilage which runs through the whole of that fold. Five processes of the cartilage are continued into the soft striated margin in which the disk terminates posteriorly. The surface of the disk is coated with thick epidermis, like the sole of the foot of higher animals. The epidermis is divided into many polygonal plates; there are no such plates between the roots of the ventral fins.

Not less unique is the structure of the bones which have some relation to this external adhesive apparatus. As exemplified by Chorismochismus dentex the coracoid is well developed, and, as usual, composed of two pieces, the upper of which is not suspended from the humerus, but fixed by a ligament to the hinder margin of the carpal bones. It is a broad lamella, dilated posteriorly into the cartilage, which is externally visible; the lower piece is narrower, and fixed to the extremity of the pubic bone of its side. The pubic bones are united by suture, and form together a heart-shaped disk, the point of which is produced backwards. The anterior portion of the disk is concave, with a bony longitudinal bridge and a feeble transverse ridge. The disk is fixed to the humeral bones by the convex portions of its anterior margin, whilst the convex portions of the lateral margins serve as base for the ventral fins. The latter are composed of one spine, which is transformed into a broad, thin, and curved plate, hidden below the skin, and apparently of four rays; but on closer examination we find that the hidden ray has a longitudinal groove anteriorly, in which another thinner ray lies concealed. This ray is quite free, and not joined to the pubic bone.

The fishes belonging to the single family of this division, Gobiesocidæ, are strictly marine but littoral fishes. They are scattered over the temperate zones of both hemispheres, and more numerous than between the Tropics. All are of small or very small size.

Fig. 232.—Gobiesox cephalus.

The adhesive disk consists of an anterior and posterior division. In some of the genera the posterior division has no free anterior margin, the teeth being either all conical, as in Chorisochismus (Cape of Good Hope) and Cotylis (Red Sea and Indian Ocean); or incisor-like in both jaws, as in Sicyases (coast of Chili and West Indies); or incisor-like at least in the lower jaw, as in Gobiesox (West Indies and Pacific coasts of South America). In other genera the posterior portion of the adhesive disk has a free anterior margin. Only one of these genera has incisor-like teeth, viz. Diplocrepis from New Zealand. In the remaining genera, Crepidogaster (from Tasmania and South Australia), Trachelochismus (from New Zealand and the Fiji Islands), Lepadogaster, and Leptopterygius, the teeth are very small and fine. The two last genera are European, and Lepadogaster at least is common on the Southern British coasts. The three species known as British—L. gouanii, L. candollii, and L. bimaculatus—are prettily coloured, but subject to great variation.

Fig. 233.—Diplocrepis puniceus.

Fifteenth Division—Acanthopterygii Channiformes.

Body elongate, covered with scales of moderate size; no spine in any of the fins; dorsal and anal long. No superbranchial organ, only a bony prominence on the anterior surface of the hyomandibular.

These fishes belong to the single family Ophiocephalidæ, Freshwater-fishes characteristic of the Indian region, which, however, have found their way into Africa, where they are represented by one or two species. Thirty-one species are known altogether, most of which are extremely abundant; some attain to a length of more than two feet. Like other tropical freshwater fishes, they are able to survive droughts, living in semi-fluid mud, or lying in a torpid state below the hard-baked crusts of the bottom of a tank from which every drop of water has disappeared. Respiration is probably entirely suspended during the state of torpidity, but whilst the mud is still soft enough to allow them to come to the surface, they rise at intervals to take in a quantity of air, by means of which their blood is oxygenised. This habit has been observed in some species to continue also to the period of the year in which the fish lives in normal water, and individuals which are kept in a basin and prevented from coming to the surface and renewing the air for respiratory purposes, are suffocated. The particular manner in which the accessory branchial cavity participates in respiratory functions is not known. It is a simple cavity, without an accessory branchial organ, the opening of which is partly closed by a fold of the mucous membrane.

Fig. 234.—Ophiocephalus striatus, India.

Sixteenth Division—Acanthopterygii Labyrinthibranchii.

Body compressed, oblong or elevated, with scales of moderate size. A superbranchial organ in a cavity accessory to that of the gills.

First Family—Labyrinthici.

Dorsal and anal spines present, but in variable numbers; ventrals thoracic. Lateral line absent, or more or less distinctly interrupted. Gill-opening rather narrow, the gill-membranes of both sides coalescent below the isthmus, and scaly; gills four; pseudobranchiæ rudimentary or absent.

Fig. 235.—Superbranchial organ of Anabas.

Freshwater-fishes of the Cyprinoid division of the Equatorial zone. They possess the faculty of being able to live for some time out of the water, or in thick or hardened mud, in a still greater degree than the fishes of the preceding family. In the accessory branchial cavity there is lodged a laminated organ which evidently has the function of assisting in the oxygenisation of the blood. In Anabas it is formed by several exceedingly thin bony laminæ, similar in form to the auricle, and concentrically situated one above the other, the innermost being the largest. The degree in which these laminæ are developed is dependent on age. In specimens from one inch and a half to two inches and a half long there are only two such laminæ, a third being indicated by a small protuberance at the central base of the second or outer laminæ. In specimens of from three to four inches in length the third lamina is developed, covering one-half of the second. The edges of all the laminæ are straight, not valanced. In specimens of from four to five inches a fourth lamina makes its appearance in the basal centre of the third lamina. The other laminæ continue to grow in their circumference, and their edges now become undulated and slightly frilled. Cuvier and Valenciennes have examined still larger specimens. The figure given by them and reproduced here was taken from a specimen six or seven inches long, and shows the superbranchial organ composed of six laminæ.

The air-bladder of the majority of these fishes is very large, extending far into the tail, and, therefore, divided behind by the hæmal spines into two lateral portions.

The Labyrinthici are generally of small size; they are capable of being domesticated, and some of them deserve particular attention on account of the dazzling beauty of their colours or the flavour of their flesh.

Anabas.—Body compressed, oblong; præorbital and orbitals serrated. Small teeth in the jaws and on the vomer; none on the palatines. Dorsal and anal spines numerous. Lateral line interrupted.

The “Climbing Perch” (A. scandens) is generally distributed over the Indian Region, and well known from its faculty of moving for some distance over land, and even up inclined surfaces. In 1797 Daldorf, in a memoir communicated to the Linnean Society of London, mentions that in 1791 he had himself taken an Anabas in the act of ascending a palm tree which grew near a pond. The fish had reached the height of five feet above the water, and was going still higher. In the effort to do this it held on to the bark of the tree by the preopercular spines, bent its tail, and stuck in the spines of the anal; then released its head, and, raising it, took a new hold with the preoperculum higher up. The fish is named in the Malayan language the “Tree Climber.” It rarely attains a length of seven inches.

Spirobranchus from the Cape, and Ctenopoma from Tropical Africa, represent Anabas in that continent.

Polyacanthus.—Body compressed, oblong; operculum without spines or serrature; cleft of the mouth small, more or less oblique, not extending beyond the vertical from the orbit, and little protractile. Small fixed teeth in the jaws, none on the palate. Dorsal and anal spines numerous; the soft dorsal and anal, the caudal, and the ventral, more or less elongate in mature specimens. Caudal rounded. Lateral line interrupted or absent.

This genus is represented chiefly in the East Indian Archipelago; seven species are known; some of them have been domesticated on account of the beauty of their colours, and several varieties have been produced. One of them is to be mentioned, as, under the name of “Paradise-fish,” it has been introduced into the aquaria of Europe, where it readily breeds. It was known already to Lacépède, and has been mentioned since his time in all ichthyological works as Macropus viridi-auratus. In adult males some of the rays, and especially the caudal lobes, are much prolonged.

Osphromenus.—Body compressed, more or less elevated; operculum without spine or serrature. Small fixed teeth in the jaws, none on the palate. Dorsal spines in small or moderate number; anal spines in moderate or great number; ventral fins with the outer ray very long, filiform. Lateral line not interrupted or absent.

Fig. 236.—Osphromenus olfax.

To this genus belongs the celebrated “Gourami” (Osphromenus olfax), reputed to be one of the best flavoured Freshwater-fishes in the East-Indian Archipelago. Its original home is Java, Sumatra, Borneo, and several other islands; but thence it has been transported to, and acclimatised in, Penang, Malacca, Mauritius, and even Cayenne. Being an almost omnivorous fish and tenacious of life, it seems to recommend itself particularly for acclimatisation in other tropical countries, and specimens kept in captivity become as tame as carps. It attains the size of a large turbot. A second, but much smaller, species of this genus, O. trichopterus, is frequently kept in vessels on account of the exquisite beauty of its varying iridescent metallic tints; like other fishes of this family it is very pugnacious.

Trichogaster, a very common Bengalese fish, differs from Osphromenus in having the ventral fins reduced to a single long filament.

Betta.—Body compressed, oblong; operculum without spine or serrature. Small fixed teeth in the jaws, none on the palate. Dorsal fin short, on the middle of the back, without any pungent spine; anal fin long. Ventral fin with five soft rays, the outer one being produced. Lateral line interrupted or absent.

A species of this genus (B. pugnax) is, on account of its pugnacious habits, reared by the Siamese. Cantor gives the following account:—“When the fish is in a state of quiet, its dull colours present nothing remarkable; but if two be brought together, or if one sees its own image in a looking-glass, the little creature becomes suddenly excited, the raised fins and the whole body shine with metallic colours of dazzling beauty, while the projected gill membrane, waving like a black frill round the throat, adds something of grotesqueness to the general appearance. In this state it makes repeated darts at its real or reflected antagonist. But both, when taken out of each other’s sight, instantly become quiet. This description was drawn up in 1840, at Singapore, by a gentleman who had been presented with several by the King of Siam. They were kept in glasses of water, fed with larvæ of mosquitoes, and had thus lived for many months. The Siamese are as infatuated with the combats of these fish as the Malays are with their cock-fights; and stake on the issue considerable sums, and sometimes their own persons and families. The license to exhibit fish-fights is farmed, and brings a considerable annual revenue to the King of Siam. The species abounds in the rivulets at the foot of the hills of Penang. The inhabitants name it ‘Pla-kat,’ or the ‘Fighting-fish;’ but the kind kept especially for fighting is an artificial variety cultivated for the purpose.”

Micracanthus.—This genus represents the three last-named genera in Africa, where it has been recently discovered in tributaries of the river Ogooué. It seems to differ from the Indian genera chiefly by its more elongate body, the structure of the fins being scarcely different (D. 3/7, A. 4/23, V. 1/4).

Second Family—Luciocephalidæ.

Body elongate, covered with scales of moderate size. Lateral line present. Teeth small. Gill-opening wide; pseudobranchiæ none. The superbranchial organ is formed by two branchial arches, which are dilated into a membrane. One short dorsal fin; dorsal and anal spines none; ventrals composed of one spine and five rays. Air-bladder none.

A small Freshwater-fish (Luciocephalus pulcher), from the East-Indian Archipelago.

Seventeenth Division—Acanthopterygii lophotiformes.

Body riband shaped, with the vent near its extremity; a short anal behind the vent; dorsal fin as long as the body.

Only one species is known of this division or family, Lophotes cepedianus. It is most probably a deep-sea fish, but does not descend to so great a depth as the Trachypteridæ, its bony and soft parts being well coherent. It is a scarce fish, hitherto found in the Mediterranean, off Madeira, and in the Sea of Japan; its length is known to exceed five feet. The head is elevated into a very high crest, and the dorsal fin commences with an exceedingly strong and long spine on the head. Silvery, with rose-coloured fins.

Eighteenth Division—Acanthopterygii Tæniiformes.

Body riband shaped; dorsal fin as long as the body; anal absent; caudal rudimentary, or not in the longitudinal axis of the fish.

Fig. 237.—Trachypterus tænia.

The “Ribbon-fishes” are true deep-sea fishes, met with in all parts of the oceans, generally found when floating dead on the surface, or thrown ashore by the waves. Their body is like a band, specimens of from fifteen to twenty feet long being from ten to twelve inches deep, and about an inch or two broad at their thickest part. The eye is large and lateral; the mouth small, armed with very feeble teeth; the head deep and short. A high dorsal fin runs along the whole length of the back, and is supported by extremely numerous rays; its foremost portion, on the head, is detached from the rest of the fin, and composed of very elongate flexible spines. The anal fin is absent. The caudal fin (if preserved, which is rarely the case, in adult specimens) has an extra-axial position, being directed upwards like a fan. The ventrals are thoracic, either composed of several rays or reduced to a single long filament. The coloration is generally silvery, with rosy fins.

When these fishes reach the surface of the water the expansion of the gases within their body has so loosened all parts of their muscular and bony system, that they can be lifted out of the water with difficulty only, and nearly always portions of the body and fins are broken and lost. The bones contain very little bony matter, are very porous, thin and light. At what depths Ribbon-fishes live is not known; probably the depths vary for different species; but although none have been yet obtained by means of the deep-sea dredge, they must be abundant at the bottom of all oceans, as dead fishes or fragments of them are frequently obtained. Some writers have supposed from the great length and narrow shape of these fishes that they have been mistaken for “Sea-serpents;” but as these monsters of the sea are always represented by those who have had the good fortune of meeting with them as remarkably active, it is not likely that harmless Ribbon-fishes, which are either dying or dead, have been the objects described as “Sea-serpents.”

Fig. 238.—Young Trachypterus.

Young Ribbon-fishes (from two to four inches) are not rarely met with near the surface; they possess the most extraordinary development of fin rays observed in the whole class of fishes, some of them being several times longer than the body, and provided with lappet-like dilatations. There is no doubt that fishes with such delicate appendages are bred and live in depths where the water is absolutely quiet, as a sojourn in the disturbed water of the surface would deprive them at once of organs which must be of some utility for their preservation.

Ribbon-fishes are divided into three genera:—

Trachypterus.—In which the ventral rays are well developed, and composed of several more or less branched rays. Specimens of this genus have been taken in the Mediterranean, Atlantic, at Mauritius, and in the Eastern Pacific. The “Deal-fish” (T. arcticus) is often met with in the North Atlantic, and specimens are generally found after the equinoctial gales on the coasts of the Orkneys and North Britain.

Stylophorus.—Without ventrals, and with the tail terminating in an exceedingly long cord-like appendage. Known from one specimen only, found at the beginning of this century between Cuba and Martinique. It is eleven inches long, and preserved in the Museum of the Royal College of Surgeons in London.

Regalecus.—Each ventral fin is reduced to a long filament, dilated at the extremity; caudal fin rudimentary or absent. These are the largest of all Ribbon-fishes, specimens being on record the length of which exceeded twenty feet. They have been taken in the Mediterranean, North and South Atlantic, Indian Ocean, and on the coast of New Zealand. They are frequently called “Kings of the herrings,” from the erroneous notion that they accompany the shoals of herrings; or “Oar-fishes,” from their two ventral fins, which have a dilatation at their extremity not unlike the blade of an oar. One or more species (R. banksii) are sometimes found on the British coasts, but they are very scarce, not more than sixteen captures having been recorded between the years 1759 and 1878.

Nineteenth Division—Acanthopterygii Notacanthiformes.

Dorsal fin short, composed of short, isolated spines, without a soft portion. Anal fin very long, anteriorly with many spines; ventrals abdominal, with more than five soft and several unarticulated rays.

Notacanthus is the most aberrant type of Acanthopterygians. Of the characteristics of this order the development of spines in the vertical fins is the only one preserved in the fishes of this genus. Their body is elongate, covered with very small scales; the snout protrudes beyond the mouth. Eyes lateral, of moderate size; dentition feeble. Five species are known from the Arctic Ocean, Mediterranean, Atlantic, and Southern Pacific. They inhabit considerable depths, probably from 100 to 400 fathoms, and during the “Challenger” expedition specimens have been obtained from an alleged depth of 1875 fathoms.

SECOND ORDER:

ACANTHOPTERYGII PHARYNGOGNATHI.

Part of the rays of the dorsal, anal, and ventral fins are non-articulated spines. The lower pharyngeals coalesced. Air-bladder without pneumatic duct.

Fig. 239.—Coalescent Pharyngeals of Scarus cretensis. a, upper; b, lower pharyngeals.

First Family—Pomacentridæ.

Body short, compressed, covered with ctenoid scales. Dentition feeble; palate smooth. The lateral line does not extend to the caudal fin, or is interrupted. One dorsal fin, with the spinous portion as well developed as the soft, or more. Two, sometimes three, anal spines; the soft anal similar to the soft dorsal. Ventral fins thoracic, with one spine and five soft rays. Gills three and a half; pseudobranchiæ and air-bladder present. Vertebræ, twelve abdominal and fourteen caudal.

Fig. 240.—Dascyllus aruanus. Natural size, from the Indo-Pacific.

The fishes of this family are marine; they resemble the Chætodonts with regard to their mode of life, living chiefly in the neighbourhood of coral formations. Like them they are beautifully coloured, the same patterns being sometimes reproduced in members of both families, proving that the development and distribution of colours is due to the agencies of climate, of the surroundings and of the habits of animals. The geographical range of the Pomacentridæ is co-extensive with that of the Chætodonts, the species being most numerous in the Indo-Pacific and Tropical Atlantic, a few extending northwards to the Mediterranean and Japan, southwards to the coasts of South Australia. They feed chiefly on small marine animals, and such as have compressed teeth appear to feed on the small Zoophytes covering the banks, round which these “Coral-fishes” abound. In a fossil state this family is known from a single genus only, Odonteus, from Monte Bolca, allied to Heliastes. The recent genera belonging to this family are:—Amphiprion, Premnas, Dascyllus, Lepidozygus, Pomacentrus, Glyphidodon, Parma, and Heliastes. About 120 species are known.

Second Family—Labridæ.

Body oblong or elongate, covered with cycloid scales. The lateral line extends to the caudal, or is interrupted. One dorsal fin, with the spinous portion as well developed as, or more than, the soft. The soft anal similar to the soft dorsal. Ventral fins thoracic, with one spine and five soft rays. Palate without teeth. Branchiostegals five or six; gills three and a half; pseudobranchiæ and air-bladder present. Pyloric appendages none; stomach without cæcal sac.

Fig. 241.—Lips of a Wrasse, Labrus festivus.

The “Wrasses” are a large family of littoral fishes, very abundant in the temperate and tropical zones, but becoming scarcer towards the Arctic and Antarctic circles, where they disappear entirely. Many of them are readily recognised by their thick lips, which are sometimes internally folded, a peculiarity which has given to them the German term of “Lip-fishes.” They feed chiefly on mollusks and crustaceans, their dentition being admirably adapted for crushing hard substances. Many species have a strong curved tooth at the posterior extremity of the intermaxillary, for the purpose of pressing a shell against the lateral and front teeth by which it is crushed. Other Wrasses feed on corals, others on zoophytes; a few are herbivorous. In all Wrasses the upper pharyngeal bones seem to be jointed to the basi-occipital; but whilst in Labrus the basi-occipital is raised on each side into a large flattish condyle, fitting into a concavity of the upper pharyngeals, in Scarus the mode of articulation is reversed, the basi-occipital having a pair of long grooves, in which the oblong condyles of the upper pharyngeals slide forwards and backwards. Beautiful colours prevail in this family, permanent pigmentary colours as well as passing iridescent reflections of the scales. Some species remain very small, others grow to a weight of fifty pounds. The larger kinds especially are prized as food, the smaller less so.

Remains of Labridæ, recognised by their united pharyngeals, which bear molar-like teeth, are not scarce in tertiary formations of France, Germany, Italy, and England. Such remains from Monte Bolca and the Swiss Molasse have been referred to the genus Labrus. Others, Nummopalatus and Phyllodus, are allied, but cannot be assigned, to one of the recent genera; the latter genus is first represented in cretaceous formations of Germany. Another genus, Taurinichthys, from the Miocene of France, represents the Odacina of the living fauna. Egertonia, from the Isle of Sheppey, differs so much from all recent Labroid genera that its pertinence to this family appears doubtful.

[See J. Cocchi, Monografia dei Pharyngodopilidæ, 1866; and E. Sauvage, Sur le genre Nummopalatus, in Bull. Soc. Geol. France, 1875.]

Labrus.—Body compressed, oblong, covered with scales of moderate size, in more than forty transverse series; snout more or less pointed; imbricate scales on the cheeks and opercles; none or only a few on the interoperculum. Teeth in the jaws conical, in a single series. Dorsal spines numerous, thirteen or twenty-one, none of which are prolonged; anal spines three. Lateral line not interrupted.

Young “Wrasses” differ from mature specimens in having the præoperculum serrated. The headquarters of this genus are the Mediterranean, whence it ranges, gradually diminishing towards the north, along all the shores of Europe. Nine species are known; British are the “Ballan Wrasse” (L. maculatus), and the “Striped or Red Wrasse” or “Cook” (L. mixtus). The two sexes of the latter species are very differently coloured; the male being generally ornamented with blue streaks, or a blackish band along the body, whilst the female has two or three large black blotches across the back of the tail.

Crenilabrus are Labrus with serrated præoperculum; the number of their dorsal spines varies from thirteen to eighteen, and the scales are arranged in less than forty transverse series.

The range of this genus is co-extensive with Labrus. C. melops, the “Gold-sinny,” or “Cork-wing,” is common on the British coasts.

Tautoga.—Body compressed, oblong, covered with small scales; scales on the cheek rudimentary, opercles naked. Teeth in the jaws conical, in double series; no posterior canine tooth. Dorsal spines seventeen, anal spines three. Lateral line not interrupted.

The “Tautog,” or “Black-fish,” is common on the Atlantic coasts of temperate North America, and much esteemed as food.

Ctenolabrus.—Body oblong, covered with scales of moderate size; imbricate scales on the cheeks and opercles. Teeth in the jaws in a band, with an outer series of stronger conical teeth; no posterior canine tooth. Dorsal spines from sixteen to eighteen; anal spines three. Lateral line not interrupted.

Four species, from the Mediterranean and the temperate parts of the North Atlantic, Ct. rupestris being common on the British, and Ct. burgall on the North American coasts.

Acantholabrus.—A Wrasse with five or six anal spines, and with the teeth in a band.

From the Mediterranean and British coasts (A. palloni).

Centrolabrus.—Wrasses with four or five anal spines, and with the teeth in a single series.

Two species are known from Madeira and the Canary Islands, and one from northern Europe and Greenland. The latter is scarce on the British coasts, but bears a distinct name on the south coast, where it is called “Rock-cook.”

Lachnolaemus from the West Indies, and Malacopterus from Juan Fernandez, are Labroids, closely allied to the preceding North Atlantic genera.

Cossyphus.—Body compressed, oblong, with scales of moderate size; snout more or less pointed; imbricate scales on the cheeks and opercles; basal portion of the vertical fins scaly. Lateral line not interrupted. Teeth in the jaws in a single series; four canine teeth in each jaw anteriorly; a posterior canine tooth. Formula of the fins: D. 12/9–11, A. 3/12.

Twenty species are known from the tropical zone and coasts adjoining it; some, like G. gouldii from Tasmania, attain a length of three or four feet.

Chilinus.—Body compressed, oblong, covered with large scales; lateral line interrupted; cheeks with two series of scales; præoperculum entire; teeth in a single series, two canines in each jaw; no posterior canine tooth; lower jaw not produced backwards. Dorsal spines subequal in length; formula of the fins: D. 9–10/10–9, A. 3/8.

Common in the tropical Indo-Pacific, whence more than twenty species are known. Hybrids between the different species of this genus are not uncommon.

Epibulus.—Closely allied to the preceding genus, but with a very protractile mouth, the ascending branches of the intermaxillaries, the mandibles, and the tympanic being much prolonged.

This fish (E. insidiator) is said to seize marine animals by suddenly thrusting out its mouth and engulphing those that come within the reach of the elongated tube. It attains a length of twelve inches, is common in the tropical Indo-Pacific, and varies much in coloration.

Anampses.—Distinguished by its singular dentition, the two front teeth of each jaw being prominent, directed forwards, compressed, with cutting edge. D. 9/12, A. 3/12.

Beautifully coloured fishes from the tropical Indo-Pacific. Ten species.

Platyglossus.—Scales in thirty or less transverse series; lateral line not interrupted. A posterior canine tooth. Dorsal spines nine.

Small beautifully coloured Coral-fishes, abundant in the equatorial zone and the coasts adjoining it. Some eighty species are known (inclusive of the allied genera Stethojulis, Leptojulis, and Pseudojulis).

Novacula.—Body strongly compressed, oblong, covered with scales of moderate size; head compressed, elevated, obtuse, with the supero-anterior profile more or less parabolic; head nearly entirely naked. Lateral line interrupted. No posterior canine tooth. D. 9/12, A. 3/12; the two anterior dorsal spines sometimes remote or separate from the others.

Twenty-six species are known from the tropical zone, and the warmer parts of the temperate zones. They are readily recognised by their compressed, knife-shaped body, and peculiar physiognomy; they scarcely exceed a length of twelve inches.

Julis.—Scales of moderate size; lateral line not interrupted. Head entirely naked. Snout of moderate extent, not produced; no posterior canine tooth. Dorsal spines ten.

Co-extensive with Platyglossus in their geographical distribution, and of like beautiful coloration and similar habits. Some of the most common fishes of the Indo-Pacific, as J. lunaris, trilobata, and dorsalis, belong to this genus.

Coris.—Scales small, in fifty or more transverse series; lateral line not interrupted. Head entirely naked. Dorsal spines nine.

Twenty-three species, distributed like Platyglossus; two reach the south coast of England, Coris julis and C. giofredi, said to be male and female of the same species. Some belong to the most gorgeously coloured kinds of the whole class of fishes.

Genera allied to the preceding Labroids are—Choerops, Xiphochilus, Semicossyphus, Trochocopus, Decodon, Pteragogus, Clepticus, Labrichthys, Labroides, Duymæria, Cirrhilabrus, Doratonotus, Pseudochilinus, Hemigymnus, Gomphosus, Cheilio, and Cymolutes.

Pseudodax.—Scales of moderate size; lateral line continuous; cheeks and opercles scaly. Each jaw armed with two pairs of broad incisors, and with a cutting lateral edge; teeth of the lower pharyngeal confluent, pavement-like. Dorsal spines eleven.

One species (P. moluccensis) from the East Indian Archipelago.

Scarus.—Jaws forming a sharp beak, the teeth being soldered together. The lower jaw projecting beyond the upper. A single series of scales on the cheek; dorsal spines stiff, pungent; the upper lip double in its whole circuit. The dentigerous plate of the lower pharyngeal is broader than long.

The fishes of this genus, and the three succeeding, are known by the name of “Parrot-wrasses.” Of Scarus one species (S. cretensis) occurs in the Mediterranean, and nine others in the tropical Atlantic. The first was held in high repute by the ancients, and Aristotle has several passages respecting its rumination. It was most plentiful and of the best quality in the Carpathian Sea, between Crete and Asia Minor, but was not unknown even in early times on the Italian coasts, though Columella says that it seldom passed beyond Sicily in his day. But in the reign of Claudius, according to Pliny, Optatus Elipentius brought it from the Troad, and introduced it into the sea between Ostium and Campagna. For five years all that were caught in the nets were thrown into the sea again, and from that time it was an abundant fish in that locality. In the time of Pliny it was considered to be the first of fishes (Nunc Scaro datur principatus); and the expense incurred by Elipentius was justified, in the opinion of the Roman gourmands, by the extreme delicacy of the fish. It was a fish, said the poets, whose very excrements the gods themselves were unwilling to reject. Its flesh was tender, agreeable, sweet, easy of digestion, and quickly assimilated; yet if it happened to have eaten an Aplysia, it produced violent diarrhœa. In short, there is no fish of which so much has been said by ancient writers. In the present day the Scarus of the Archipelago is considered to be a fish of exquisite flavour; and the Greeks still name it Scaro, and eat it with a sauce made of its liver and intestines. It feeds on fucus; and Valenciennes thinks that the necessity for masticating its vegetable diet thoroughly, and the working of it with that intent backwards and forwards in the mouth, may have given rise to the notion of its being a ruminant; and it is certain that its aliment is very finely divided when it reaches the stomach.

Fig. 242.—Scarichthys auritus.

Scarichthys.—Differing from Scarus only in having flexible dorsal spines.

Two species from the Indo-Pacific.

Callyodon.—Differing from Scarichthys in having the upper lip double posteriorly only.

Nine species from the tropical zone.

Pseudoscarus.—Jaws forming a strong beak, the teeth being soldered together. The upper jaw projecting beyond the lower. Two or more series of scales on the cheek. The dentigerous plate of the lower pharyngeal longer than broad.

This tropical genus contains by far the greatest number of Scaroid Wrasses, some seventy species being known, and a still greater number of names being introduced into the various Ichthyological works. They are beautifully coloured, but the colours change with age, and vary in an extraordinary degree in the same species. They rapidly fade after death, so that it is almost impossible to recognise in preserved specimens the species described from living individuals. Many attain to a rather large size, upwards of three feet in length. The majority are eaten, but some acquire poisonous properties from their food, which consists either of corals or of fucus.

Odax.—The edge of each jaw is sharp, without distinct teeth. The dentigerous plate of the lower pharyngeal triangular, much broader than long. Cheeks and opercles scaly; scales of the body small or rather small; lateral line continuous. Snout conical. Dorsal spines rather numerous, flexible.

Fig. 243.—Odax radiatus.

Six species from the coasts of Australia and New Zealand. Small. The species figured (O. radiatus) is from Western Australia.

Coridodax.—Jaws as in Odax, head naked. Scales of the body small; lateral line continuous. Snout of moderate extent. Dorsal spines numerous, flexible.

The “Butter-fish,” or “Kelp-fish” of the colonists of New Zealand (C. pullus), is prized as food, and attains to a weight of four or five pounds. It feeds on zoophytes, scraping them from the surface of the kelp, with its curiously formed teeth. Its bones are green, like those of Belone.

Olistherops, from King George’s Sound, has scales of moderate size, but agrees otherwise with Coridodax.

Siphonognathus.—Head and body very elongate, snout long, as in Fistularia; upper jaw terminating in a long, pointed, skinny appendage; opercles and cheeks scaly; scales of moderate size; lateral line continuous. Dorsal spines numerous, flexible. Jaws as in Odax; the dentigerous plate of the lower pharyngeal very narrow.

S. argyrophanes, from King George’s Sound, is the most aberrant type of Wrasses, whose principal characters are retained, but united with a form of the body which resembles that of a Pipe-fish.

Third Family—Embiotocidæ.

Body compressed, elevated or oblong, covered with cycloid scales; lateral line continuous. One dorsal fin, with a spinous portion, and with a scaly sheath along the base, which is separated by a groove from the other scales; anal with three spines and numerous rays; ventral fins thoracic, with one spine and five rays. Small teeth in the jaws, none on the palate. Pseudobranchiæ present. Stomach siphonal, pyloric appendages none. Viviparous.

Marine Fishes characteristic of the fauna of the temperate North Pacific, the majority living on the American side, and only a few on the Asiatic. All are viviparous (see Fig. [70], p. 159). Agassiz describes the development of the embryoes as a normal ovarian gestation, the sac containing the young not being the oviduct but the ovarian sheath, which fulfils the functions of the ovary. This organ presents two modes of arrangement: in one there is a series of triangular membranous flaps communicating with each other, between which the young are arranged, mostly longitudinally, the head of one to the tail of another, but sometimes with the bodies curved, to the number of eighteen or twenty; in the other, the cavity is divided by three membranes converging to a point, into four compartments, not communicating with each other except towards the genital opening, the young being arranged in the same longitudinal manner. The proportionate size of the young is very remarkable. In a female specimen 10½ inches long, and 4½ inches high, the young were nearly 3 inches long and 1 inch high. Seventeen species are known, the majority of which belong to Ditrema, and one to Hysterocarpus. They do not attain to a large size, varying from three-quarters to three pounds in weight.

Fourth Family—Chromides.

Body elevated, oblong or elongate, scaly, the scales being generally ctenoid. Lateral line interrupted or nearly so. One dorsal fin, with a spinous portion; three or more anal spines; the soft anal similar to the soft dorsal. Ventral fins thoracic, with one spine and five rays. Teeth in the jaws small, palate smooth. Pseudobranchiæ none. Stomach coecal; pyloric appendages none.

Freshwater-fishes of rather small size from the tropical parts of Africa and America; one genus from Western India. The species with lobate teeth, and with many circumvolutions of the intestines, are herbivorous, the other carnivorous.

Etroplus.—Body compressed, elevated, covered with ctenoid scales of moderate size. Lateral line indistinct. Dorsal and anal spines numerous. Teeth compressed, lobate, in one or two series. Anterior prominences of the branchial arches not numerous, short, conical, hard. Dorsal fin not scaly.

Two species from Ceylon and Southern India.

Chromis.—Body compressed, oblong, covered with cycloid scales of moderate size. Dorsal spines numerous, anal spines three. Teeth compressed, more or less lobate, in one series. Anterior prominences of the branchial arches short, thin, lamelliform, non-serrated. Dorsal fin not scaly.

Some twenty species are known from the fresh waters of Africa and Palestine; the most celebrated is the “Bulti,” or “Bolty,” of the Nile, one of the few well-flavoured fishes of that river; it grows to the length of twenty inches. Two or three species of this genus occur in the Jordan and Lake of Galilee.

Fig. 244.—Chromis andreæ, from the Lake of Galilee.

Hemichromis, differing from Chromis in having conical teeth in one or two series.

Ten species, the range of which is co-extensive with that of Chromis. One species, H. sacra, is abundant in the Lake of Galilee.

Paretroplus, differing from Hemichromis in having nine anal spines.

One species from Madagascar.

Acara.—Body compressed, oblong, covered with ctenoid scales of moderate size. Dorsal spines numerous, anal spines three or four; base of the soft dorsal nearly uncovered by scales. Teeth in a band, small, conical. Anterior prominences of the first branchial arch very short tubercles.

Some twenty species are known from the fresh waters of Tropical America, A. bimaculata being one of the most common fishes of that region. All are very small.

Heros.—Differing from Acara in having more than four anal spines.

Some fifty species are known from the fresh waters of Tropical America, especially Central America, where almost every large lake or river is tenanted by one or more peculiar species. They are of rather small size, rarely exceeding a length of twelve inches.

Fig. 245.—Heros salvini, from Central America.

Genera allied to Heros, and likewise from Tropical America, are Neetroplus, Mesonauta, Petenia, Uaru, and Hygrogonus.

Cichla.—Form of the body perch-like. Scales small; the spinous and soft portions of the dorsal fin of nearly equal extent, and separated by a notch; anal spines three. Each jaw with a broad band of villiform teeth. The outer branchial arch with lanceolate crenulated prominences along its concave side. Dorsal and anal fins scaly.

Four species from Brazil, Guyana, and Peru.

Crenicichla.—Body low, sub-cylindrical; scales small or rather small. The spinous portion of the dorsal is much more developed than the soft, both being continuous, and not separated by a notch; anal spines three. Præopercular margin serrated. Each jaw with a band of conical teeth. The outer branchial arch with short tubercles. Dorsal and anal fins naked.

Ten species from Brazil and Guyana.

The following genera complete the list of South American Chromides: Chætobranchus, Mesops, Satanoperca, Geophagus, Symphysodon, and Pterophyllum.

THIRD ORDER—ANACANTHINI.

Vertical and ventral fins without spinous rays. The ventral fins, if present, are jugular or thoracic. Air-bladder, if present, without pneumatic duct.

These characters are common to all the members of this order, with the exception of a freshwater-fish from Tasmania and South Australia (Gadopsis), which has the anterior portion of the dorsal and anal fins formed of spines.

First Division—Anacanthini Gadoidei.

Head and body symmetrically formed.

First Family—Lycodidæ.

Vertical fins confluent. Ventral fin, if present, small, attached to the humeral arch, jugular. Gill-opening narrow, the gill-membrane being attached to the isthmus.

Marine littoral fishes of small size, resembling Blennies, chiefly represented in high latitudes, but a few living within the tropical zone.

Lycodes.—Body elongate, covered with minute scales imbedded in the skin, or naked; lateral line more or less indistinct. Eye of moderate size. Ventral small, short, rudimentary, jugular, composed of several rays. Upper jaw overlapping the lower. Conical teeth in the jaws, on the vomer, and on the palatine bones. Barbel none. Five or six branchiostegals; gill-opening narrow, the gill-membranes being attached to the isthmus. Pseudobranchiæ present. Air-bladder none. Pyloric appendages two, or rudimentary, or entirely absent. No prominent anal papilla.

Fig. 246.—Lycodes mucosus, from Northumberland Sound.

Nine species are known from the Arctic Ocean, four from the southern extremity of the American continent.

Gymnelis.—Body elongate, naked. Eye of moderate size or rather small. Ventrals none. Vent situated at some distance backwards from the head. Small conical teeth in the jaws, on the vomer and palatine bones. Jaws equal anteriorly. Barbel none. Six branchiostegals; gill-opening narrow, the gill membranes being attached to the isthmus. Pseudobranchiæ present; air-bladder none. Pyloric appendages two; no prominent anal papilla.

Fig. 247.—Gymnelis viridis.

One species (G. viridis) from Greenland, the other (G. pictus) from the Straits of Magelhæn.

The other genera belonging to this family are Uronectes from Baffin’s Bay, Microdesmus from Panama, Blennodesmus from the coast of North-Eastern Australia, and Maynea from the Straits of Magelhæn.

Second Family—Gadidæ.

Body more or less elongate, covered with small smooth scales. One, two, or three dorsal fins, occupying nearly the whole of the back; rays of the posterior dorsal well developed; one or two anal fins. Caudal free from dorsal and anal, or, if they are united, the dorsal with a separate anterior portion. Ventrals jugular, composed of several rays, or, if they are reduced to a filament, the dorsal is divided into two. Gill-opening wide; the gill-membranes generally not attached to the isthmus. Pseudobranchiæ none, or glandular, rudimentary. An air-bladder and pyloric appendages generally present.

The family of “Cod-fishes” consists partly of littoral and surface species (and they form the majority), partly of deep-sea forms. The former are almost entirely confined to the temperate zones, extending beyond the Arctic Circle; the latter have, as deep-sea fishes generally, a much wider range, and hitherto have been found chiefly at considerable depths of rather low latitudes. Only two or three species inhabit fresh waters. They form one of the most important articles of food and subsistence to the fishermen in Europe and North America, and to whole tribes bordering upon the Arctic Ocean.

Fossil remains are scarce. Nemopteryx and Palæogadus have been described from the schists of Glaris, a formation believed to have been the bottom of a very deep sea. In the clay of Sheppey species occur allied to Gadus, Merluccius, and Phycis; others, not readily determinable, have been found at Licata in Sicily (Miocene).

Gadus.—Body moderately elongate, covered with small scales. A separate caudal, three dorsal, and two anal fins; ventrals narrow, composed of six or more rays. Teeth in the upper jaw in a narrow band; vomerine teeth; none on the palatines.

Arctic and temperate zones of the Northern Hemisphere. Eighteen species are known, of which the following are the most important:—

Gadus morrhua, the common “Cod-fish”—in German called “Kabeljau” when fresh and old, “Dorsch” when young and fresh, “Stock-fish” when dried, “Labberdan” when salted—measures from two to four feet, and attains to a weight of one hundred pounds. On the British coasts and in the German Ocean it is generally of a greenish or brownish-olive colour, with numerous yellowish or brown spots. Farther northwards darker-coloured specimens, frequently without any spots, predominate; and on the Greenland, Iceland, and North Scandinavian coasts the Cod have often a large irregular black blotch on the side. The Cod-fish occurs between 50° and 75° lat. N., in great profusion, to a depth of 120 fathoms, but is not found nearer the Equator than 40° lat. Close to the coast it is met with singly all the year round, but towards the spawning-time it approaches the shore in numbers, which happens in January in England and not before May on the American coasts. The English resorted to the cod-fisheries of Iceland before the year 1415, but since the sixteenth century most vessels go to the banks of Newfoundland, and almost all the preserved Cod consumed during Lent in the various continental countries is imported from across the Atlantic. At one time the Newfoundland cod-fishery rivalled in importance the whale-fishery and the fur trade of North America. Cod-liver oil is prepared from the liver on the Norwegian coast, but also other species of this genus contribute to this most important drug.

Gadus tomcodus abundantly occurs on the American coasts; it remains within smaller dimensions than the common Cod-fish. Gadus æglefinus, the “Haddock” (“Schell-fisch” of the Germans, “Hadot” of the French), is distinguished by a black lateral line and a blackish spot above the pectoral fin. It attains to a length of three feet in the higher latitudes, but remains smaller on more southern coasts; like the Cod it extends across the Atlantic. The largest specimens are taken on the British coast in winter, because at that time they leave the deep water to spawn on the coast. Gadus merlangus, the “Whiting,” with a black spot in the axil of the pectoral fin. Gadus luscus, the “Bib,” “Pout,” or “Whiting-pout,” with cross-bands during life, and with a black axillary spot, rarely exceeding a weight of five pounds. Gadus fabricii, a small species, but occurring in incredible numbers on the shores near the Arctic circle, and ranging to 80° lat. N. Gadus pollachius, the “Pollack,” without a barbel at the chin, and with the lower jaw projecting beyond the upper. Gadus virens, the “Coal-fish,” valuable on account of its size and abundance, and therefore preserved for export like the Cod.

The fishes of the genus Gadus are bathymetrically succeeded by several genera, as Gadiculus, Mora, and Strinsia; however these do not descend to sufficiently great depths to be included into the deep-sea Fauna; the two following are true deep-sea fishes.

Halargyreus.—Body elongate, covered with small scales. Two dorsal and two anal fins; ventrals composed of several rays. Jaws with a band of minute villiform teeth; vomer and palatines toothless. No barbel.

The single species known, H. johnsonii, proves to be a deep-sea fish by its organisation as well as geographical distribution. Originally known from a single specimen, which was obtained at Madeira, it has since been found off the coast of New Zealand. There is no doubt that it will be discovered also in intermediate seas.

Melanonus.—Head and body rather compressed, covered with cycloid scales of moderate size, and terminating in a long tapering tail, without caudal. Eye of moderate size. Villiform teeth in the jaws, on the vomer and palatine bones. Barbel none. A short anterior dorsal, the second extending to the end of the tail, and the anal being of similar length. Ventrals composed of several rays. Bones soft and flexible.

This is one of the discoveries made during the expedition of the “Challenger.” The single specimen obtained is of a deep-black colour, and was dredged up at a depth of 1975 fathoms in the Antarctic Ocean.

Merluccius.—Body elongate, covered with very small scales. A separate caudal; two dorsal fins and one anal; ventrals well developed, composed of seven rays. Teeth in the jaws and on the vomer rather strong, in double or triple series. No barbel.

Two species are known of this genus, widely separated in their distribution. The European species, M. vulgaris, the “Hake,” is found on both sides of the Atlantic, and grows to a length of four feet. It is caught in great numbers, and preserved as “Stock-fish.” The second species M. gayi, is common in the Straits of Magelhæn and on the coast of Chili, less so in New Zealand.

The vertebral column of this genus shows a singular modification of the apophyses. The neural spines of all the abdominal vertebræ are extremely strong, dilated, wedged into one another. The parapophyses of the third to sixth vertebræ are slender, styliform, whilst those of all the following abdominal vertebræ are very long and broad, convex on the upper and concave on the lower surface; the two or three anterior pairs are, as it were, inflated. The whole forms a strong roof for the air-bladder, reminding us of a similar structure in Kurtus.

Pseudophycis.—Body of moderate length, covered with rather small scales. A separate caudal, two dorsals, and one anal; ventral fins very narrow and styliform, but composed of several rays. Jaws with a band of small teeth; vomer and palatines toothless. Chin with a barbel.

Two species, of which Ps. bachus is common on the coast of New Zealand.

Allied genera are Lotella, Physiculus, Uraleptus, and Læmonema, from moderate depths, obtained chiefly off Madeira and the Southern Temperate Zone.

Fig. 248.—Pseudophycis bachus.

Phycis.—Body of moderate length, covered with small scales. Fins more or less enveloped in loose skin. A separate caudal; two dorsal fins and one anal; the anterior dorsal composed of from eight to ten rays; ventrals reduced to a single long ray, bifid at its end. Small teeth in the jaws and on the vomer; palatine bones toothless. Chin with a barbel.

Six species from the temperate parts of the North Atlantic and the Mediterranean, one, Ph. blennioides, is occasionally found on the British coast.

Haloporphyrus.—Body elongate, covered with small scales. A separate caudal, two dorsal fins, and one anal; the first dorsal with four rays; ventrals narrow, composed of six rays. Jaws and vomer with villiform teeth; palatine bones toothless. Chin with a barbel.

A small genus of deep-sea fishes, of which three species are known. They offer a striking instance of the extraordinary distribution of deep-sea fishes; H. lepidion occurs in from 100 to 600 fathoms in the Mediterranean and the neighbouring parts of the Atlantic, off the coast of Japan, and various parts of the South Atlantic; H. australis in from 55 to 70 fathoms in the Straits of Magelhæn; and finally H. rostratus in from 600 to 1375 fathoms, midway between the Cape of Good Hope and Kerguelen’s Land, and in the South Atlantic.

Lota.—Body elongate, covered with very small scales. A separate caudal, two dorsal fins, and one anal; ventrals narrow, composed of six rays. Villiform teeth in the jaws and on the vomer; none on the palatines. The first dorsal with from ten to thirteen well-developed rays. Chin with a barbel.

The “Burbot,” or “Eel-pout” (L. vulgaris, Fig. [8], p. 43), is a Freshwater-fish which never enters salt water. It is locally distributed in Central and Northern Europe and North America; it is one of the best Freshwater-fishes, and exceeds a length of three feet.

Molva.—Differs from Lota in having several large teeth in the lower jaw and on the vomer.

The “Ling” (M. vulgaris) is a very valuable species, common on the northern coasts of Europe, Iceland, and Greenland; and generally found from three to four feet long. The larger number of the specimens caught are cured and dried.

Motella.—Body elongate, covered with minute scales. A separate caudal. Two dorsal fins, the anterior of which is reduced to a narrow rayed fringe, more or less concealed in a longitudinal groove; the first ray is prolonged. One anal fin. Ventrals composed of from five to seven rays. A band of teeth in the jaws and on the vomer.

Eight species of “Rocklings” are known from the coasts of Europe, Iceland, Greenland, Japan, the Cape of Good Hope, and New Zealand. They are of small size, and chiefly distinguished by the number of their barbels. British are the Five-bearded Rockling (M. mustela), the Three-bearded Rocklings (M. tricirrhata, macrophthalma, and maculata), and the Four-bearded Rockling (M. cimbria). M. macrophthalma comes from a depth of from 80 to 180 fathoms. The young are known as “Mackerel Midge” (Couchia), and sometimes met with in large numbers at some distance from the coast.

Raniceps.—Head large, broad, and depressed; body of moderate length, covered with minute scales. A separate caudal. Two dorsal fins, the anterior of which is very short, rudimentary. One anal fin. Ventrals composed of six rays. Cardlike teeth in the jaws and on the vomer.

The “Trifurcated Hake,” R. trifurcus, not uncommon on the coasts of Northern Europe.

Bregmaceros.—Body fusiform, compressed posteriorly, covered with cycloid scales of moderate size. Two dorsal fins; the anterior reduced to a single long ray on the occiput; the second and the anal much depressed in the middle; ventrals very long, composed of five rays. Teeth small.

Fig. 249.—Bregmaceros macclellandii.

A dwarf Gadoid, the only one found at the surface between the Tropics. B. macclellandii scarcely exceeds three inches in length, is not uncommon in the Indian Ocean, and has found its way to New Zealand; specimens have been picked up in mid-ocean.

Murænolepis.—Body covered with lanceolate epidermoid productions, intersecting each other at right angles like those of a Freshwater-eel. Vertical fins confluent, no caudal being discernible; an anterior dorsal fin is represented by a single filamentous ray; ventral fins narrow, composed of several rays. A barbel. Jaws with a band of villiform teeth; palate toothless.

One species (M. marmoratus) from Kerguelen’s Land.

Chiasmodus.—Body naked; stomach and abdomen distensible. Two dorsal fins and one anal; a separate caudal; ventral fins rather narrow, with several rays. Upper and lower jaws with two series of large pointed teeth, some of the anterior being very large and movable; teeth on the palatine bones, but none on the vomer. Chin without barbel.

This Gadoid (Ch. niger, Fig. [111], p. 311), inhabits great depths in the Atlantic (to 1500 fathoms). The specimen figured was taken with a large Scopeloid in its stomach.

Brosmius.—Body moderately elongate, covered with very small scales. A separate caudal, one dorsal, and one anal; ventrals narrow, composed of five rays. Vomerine and palatine teeth. A barbel.

The “Torsk” (B. brosme) is confined to the northern parts of the temperate zone, and probably extends to the arctic circle.

Third Family—Ophidiidæ.

Body more or less elongate, naked, or scaly. Vertical fins generally united; no separate anterior dorsal or anal; dorsal occupying the greater portion of the back. Ventral fins rudimentary or absent, jugular. Gill-openings wide, the gill-membranes not attached to the isthmus.

Marine fishes (with the exception of Lucifuga), partly littoral, partly bathybial. They may be divided into five groups.

I. Ventral fins present, attached to the humeral arch: Brotulina.

Brotula.—Body elongate, covered with minute scales. Eye of moderate size. Each ventral reduced to a single filament, sometimes bifid at its extremity. Teeth villiform; snout with barbels. One pyloric appendage.

Five species of small size from the Tropical Atlantic and Indian Ocean.

Fig. 250.—Lucifuga dentata, from caves in Cuba.

Lucifuga are Brotula organised for a subterranean life. The eye is absent, or quite rudimentary, and covered by the skin; the barbels of Brotula are replaced by numerous minute ciliæ or tubercles. They inhabit the subterranean waters of caves in Cuba, and never come to the light.

Bathynectes.—Body produced into a long tapering tail, without caudal. Mouth very wide, villiform teeth in the jaws, on the vomer and palatine bones. Barbel none. Ventral fins reduced to simple or bifid filaments, placed close together, and near to the humeral symphysis. Gill-membranes not united; gill-laminæ remarkably short. Bones of the head soft and cavernous; operculum with a very feeble spine above.

Deep-sea fishes, inhabiting depths varying from 1000 to 2500 fathoms. Three species are known, the largest specimen obtained being seventeen inches long.

Fig. 251.—Acanthonus armatus.

Acanthonus.—Head large and thick, armed in front and on the opercles with strong spines; trunk very short, the vent being below the pectoral; tail thin, strongly compressed, tapering, without caudal. Eye small. Mouth very wide; villiform teeth in the jaws, on the vomer and palatine bones. Barbel none. Ventrals reduced to simple filaments placed close together on the humeral symphysis. Scales extremely small. Bones of the head soft.

Only two specimens, thirteen inches long, of this remarkable deep-sea form have been obtained, at a depth of 1075 fathoms, in the Indian Ocean.

Typhlonus.—Head large, compressed, with most of the bones in a cartilaginous condition; the superficial bones with large muciferous cavities, not armed. Snout a thick protuberance projecting beyond the mouth, which is rather small and inferior. Trunk very short, the vent being below the pectoral; tail thin, strongly compressed, tapering, without separate caudal. Eye externally not visible. Villiform teeth in the jaws, on the vomer and palatine bones. Barbel none. Scales thin, deciduous, small.

Also of this deep-sea fish two specimens only are known, 10 inches long, from a depth of 2200 fathoms in the Western Pacific.

Aphyonus.—Head, body, and tapering tail strongly compressed, enveloped in a thin, scaleless, loose skin. Vent far behind the pectoral. Snout swollen, projecting beyond the wide mouth. No teeth in the upper jaw, small ones in the lower. No externally visible eye. Barbel none. Head covered with a system of wide muciferous channels, the dermal bones being almost membranaceous, whilst the others are in a semi-cartilaginous condition. Notochord persistent, but with a superficial indication of vertebral segments.

Fig. 252.—Aphyonus gelatinosus.

One specimen only of this most remarkable form is known; it is 5½ inches long, and was obtained at a depth of 1400 fathoms south of New Guinea.

Of the remaining genera belonging to this group, Brotulophis, Halidesmus, Dinematichthys, and Bythites are surface forms; Sirembo and Pteridium inhabit moderate depths; Rhinonus is a deep-sea fish.

II. Ventral fins replaced by a pair of bifid filaments (barbels) inserted below the glossohyal: Ophidiinæ.

Ophidium.—Body elongate, compressed, covered with very small scales. Eye of moderate size. All the teeth small.

Small fishes from the Atlantic and Pacific. Seven species are known, differing from one another in the structure of the air-bladder (see p. 145).

Genypterus is a larger form of Ophidium, in which the outer series of teeth in the jaws and the single palatine series contains strong teeth.

Three species from the Cape of Good Hope, South Australia, New Zealand, and Chili are known. They grow to a length of five feet, and have an excellent flesh, like cod, well adapted for curing. At the Cape they are known by the name of “Klipvisch,” and in New Zealand as “Ling” or “Cloudy Bay Cod.”

III. No ventral fins whatever; vent at the throat: Fierasferina.

These fishes (Fierasfer and Encheliophis) are of very small size and eel-like in shape; the ten species known are found in the Mediterranean, Atlantic, and Indo-Pacific. As far as is known they live parasitically in cavities of other marine animals, accompany Medusæ, and more especially penetrate into the respiratory cavities of Star-fishes and Holothurians. Not rarely they attempt other animals less suited for their habits, as, for instance, Bivalves; and cases are known in which they have been found imprisoned below the mantle of the Mollusk, or covered over with a layer of the pearly substance secreted by it. They are perfectly harmless to their host, and merely seek for themselves a safe habitation, feeding on the animalcules which enter with the water the cavity inhabited by them.

IV. No ventral fins whatever; vent remote from the head; gill-openings very wide, the gill-membranes not being united: Ammodytina.

The “Sand-eels” or “Launces” (Ammodytes) are extremely common on sandy shores of Europe and North America. They live in large shoals, rising as with one accord to the surface, or diving to the bottom, where they bury themselves with incredible rapidity in the sand. They are much sought after for bait by fishermen, who discover their presence on the surface by watching the action of Porpoises which feed on them. These Cetaceans, when they meet with a shoal, know how to keep it on the surface by diving below and swimming round it, thus destroying large numbers of them. The most common species on the British coast is the Lesser Sand-eel (A. tobianus); the Greater Sand-eel (A. lanceolatus), which attains to a length of eighteen inches; A. siculus, from the Mediterranean, scarcer in British seas. Two species live on the American coasts, A. americanus and A. dubius; one in California, A. personatus. Bleekeria from Madras is the second genus of this group.

Fig. 253.—Congrogadus subducens.

V. No ventral fins whatever; vent remote from the head; gill-openings of moderate width, the gill-membranes being united below the throat, not attached to the isthmus: Congrogadina.

Only two fishes belong to this group—Congrogadus from the Australian coasts, and Haliophis from the Red Sea.

Fourth Family—Macruridæ.

Body terminating in a long, compressed, tapering tail, covered with spiny, keeled, or striated scales. One short anterior dorsal; the second very long, continued to the end of the tail, and composed of very feeble rays; anal of an extent similar to that of the second dorsal; no caudal. Ventral fins thoracic or jugular, composed of several rays.

Fig. 254.—Scale of Macrurus trachyrhynchus.

Fig. 255.—Scale of Macrurus cœlorhynchus.

Fig. 256.—Scale from the lateral line of Macrurus australis.

This family, known a few years ago from a limited number of examples, representing a few species only, proves to be one which is distributed over all oceans, occurring in considerable variety and great abundance at depths of from 120 to 2600 fathoms. They are, in fact, Deep-sea Gadoids, much resembling each other in the general shape of their body, but differing in the form of the snout and in the structure of their scales. About forty species are known, of which many attain a length of three feet. They have been referred to the following genera:—

Fig. 257.—Macrurus australis.

Macrurus.—Scales of moderate size; snout produced, conical; mouth inferior.

Coryphænoides.—Scales of moderate size; snout obtuse, obliquely truncated; cleft of the mouth lateral.

Macruronus.—Scales of moderate size, spiny; snout pointed; mouth anterior and lateral, with the lower jaw projecting.

Malacocephalus.—Scales very small, ctenoid; snout short, obtuse, obliquely truncated.

Bathygadus.—Scales small, cycloid; snout not projecting beyond the mouth; mouth wide, anterior, and lateral.

Ateleopus from Japan and Xenocephalus from New Ireland are genera belonging to the Gadoid Anacanths, but are very imperfectly known.

Second Division—Anacanthini Pleuronectoidei.

Head and part of the body unsymmetrically formed.

This division consists of one family only:

Pleuronectidæ.

The fishes of this family are called “Flat-fishes,” from their strongly compressed, high, and flat body; in consequence of the absence of an air-bladder, and of the structure of their paired fins, they are unable to maintain their body in a vertical position, resting and moving on one side of the body only. The side turned towards the bottom is sometimes the left, sometimes the right, colourless, and termed the “blind” side; that turned upwards and towards the light is variously, and in some tropical species even vividly, coloured. Both eyes are on the coloured side, on which side also the muscles are more strongly developed. The dorsal and anal fins are exceedingly long, without division. All the Flat-fishes undergo remarkable changes with age, which, however, are very imperfectly known and not yet fully understood, from the difficulty of referring larval forms to their respective parents. The larvæ are, singularly enough, much more frequently met in the open ocean than near the coast; they are transparent, like Leptocephali; perfectly symmetrical, with an eye on each side of the head, and swim in a vertical position like other fishes. The manner in which one eye is transferred from the blind to the coloured side is subject to discussion. Whilst some naturalists believe that the eye turning round its axis pushes its way through the yielding bones from the blind to the upper side, others hold that, as soon as the body of the fish commences to rest on one side only, the eye of that side, in its tendency to turn towards the light, carries the surrounding parts of the head with it; in fact, the whole of the fore-part of the head is twisted towards the coloured side, which is a process of but little difficulty as long as the framework of the head is still cartilaginous.

Flat-fishes when adult live always on the bottom, and swim with an undulating motion of their body. Sometimes they rise to the surface; they prefer sandy bottom, and do not descend to any considerable depth. They occur in all seas, except in the highest latitudes and on rocky, precipitous coasts, becoming most numerous towards the equator; those of the largest size occur in the temperate zone. Some enter fresh water freely, and others have become entirely acclimatised in ponds and rivers. All are carnivorous.

Flat-fishes were not abundant in the tertiary epoch; the only representative known is a species of Rhombus from Monte Bolca.

The size and abundance of Flat-fishes, and the flavour of the flesh of the majority of the species, render this family one of the most useful to man; and especially on the coasts of the northern temperate zone, their capture is one of the most important sources of profit to the fishermen.

Psettodes.—Mouth very wide, the maxillary being more than one-half of that of the head. Each jaw armed with two series of long, slender, curved, distant teeth, the front teeth of the inner series of the lower jaw being the longest, and received in a groove before the vomer; vomerine and palatine teeth. The dorsal fin commences on the nape of the neck.

This genus fitly heads the list of Flat-fishes, having retained more of symmetrical structure than the other members of the family, and, therefore, their eyes are as often found on the right as on the left side. It seems to swim, not unfrequently, in a vertical position. Only one species is known, Ps. erumei, common in the Indian Ocean.

Hippoglossus.—Eyes on the right side; mouth wide, the length of the maxillary being one-third of that of the head. Teeth in the upper jaw in a double series; the anterior of the upper jaw and the lateral of the lower strong. The dorsal fin commences above the eye.

The “Holibut” (H. vulgaris) is the largest of all Flat-fishes, attaining to a length of five and six feet, and a weight of several hundredweights. It is found along the northern coasts of Europe, on the coasts of Kamtschatka and California, particularly frequenting banks situated at some distance from the coast, and at a depth of 50 to 120 fathoms.

Other genera, with nearly symmetrical mouth, in which the dorsal fin commences above the eye, are Hippoglossoides (the “Rough Dab”) and Tephritis.

Rhombus.—Eyes on the left side. Mouth wide, the length of the maxillary being more than one-third of that of the head. Each jaw with a band of villiform teeth, without canines; vomerine teeth, none on the palatines. The dorsal fin commences on the snout. Scales none or small.

Seven species from the North Atlantic and Mediterranean, of which the most noteworthy are the “Turbot,” Rh. maximus, one of the most valued food-fishes, and growing to a length of three feet; the “Turbot of the Black Sea,” Rh. mæoticus, the body of which is covered with bony, conical tubercles, which are as large as the eye; the “Brill,” Rh. lævis, represented on the North American coasts by Rh. aquosus; the “Whiff,” or “Mary-sole,” or “Sail-fluke,” Rh. megastoma; “Bloch’s Top-knot,” Rh. punctatus (described by Yarrell as Rh. hirtus, and often confounded with the following species).

Phrynorhombus, differing from Rhombus in lacking vomerine teeth. The scales are very small and spiny.

The “Top-knot” (Ph. unimaculatus) occurs occasionally on the south coast of England, and is more common in the Mediterranean; it is a small species.

Arnoglossus.—Mouth wide, the length of the maxillary being more or not much less than one-third of that of the head. Teeth minute, in a single series in both jaws; vomerine or palatine teeth none. The dorsal fin commences on the snout. Scales of moderate size, deciduous; lateral line with a strong curve above the pectoral. Eyes on the left side.

Seven species from European and Indian Seas. The “Scald-fish” (A. laterna) is common in the Mediterranean, and extends to the south coast of England; it is a small species.

Pseudorhombus.—Mouth wide, the length of the maxillary being more than one-third of that of the head. Teeth in both jaws in a single series, of unequal size; vomerine or palatine teeth none. The dorsal fin commences on the snout. Scales small; lateral line with a strong curve anteriorly. Eyes on the left side. Interorbital space not concave.

A tropical genus with a few outlying species, represented chiefly in the Indo-Pacific, and also in the Atlantic. Seventeen species.

Rhomboidichthys.—Mouth of moderate width or small. Teeth minute, in a single or double series; vomerine or palatine teeth none. Eyes separated by a concave more or less broad space. The dorsal fin commences on the snout. Scales ciliated; lateral line with a strong curve anteriorly. Eyes on the left side.

A tropical genus, but also represented in the Mediterranean and on the coast of Japan. Sixteen species, the majority of which are prettily coloured and ornamented with ocellated spots; in some species the adult males have some of the fin-rays prolonged into filaments.

Other genera with nearly symmetrical mouth, in which the dorsal fin commences before the eye, on the snout, are Citharus, Anticitharus, Brachypleura, Samaris, Psettichthys, Citharichthys, Hemirhombus, Paralichthys, Liopsetta, Lophonectes, Lepidopsetta, and Thysanopsetta.

Pleuronectes.—Cleft of the mouth narrow, with the dentition much more developed on the blind side than on the coloured. Teeth in a single or in a double series, of moderate size; palatine and vomerine teeth none. The dorsal fin commences above the eye. Scales very small or entirely absent. Eyes generally on the right side.

This genus is characteristic of the littoral fauna of the northern temperate zone, a few species ranging to the Arctic circle. Twenty-three species are known, of which the following are the most noteworthy: P. platessa, the “Plaice,” ranging from the coast of France to Iceland; P. glacialis, from the Arctic coasts of North America; P. americanus, the transatlantic representative of the Plaice; P. limanda, the common “Dab;” P. microcephalus, the “Smear-dab;” P. cynoglossus, the “Craig-fluke;” P. flesus, the “Flounder.”

Rhombosolea.—Eyes on the right side, the lower in advance of the upper. Mouth narrower on the right side than on the left; teeth on the blind side only, villiform; palatine and vomerine teeth none. The dorsal fin commences on the foremost part of the snout. Only one ventral which is continuous with the anal. Scales very small, cycloid; lateral line straight.

This genus represents Pleuronectes in the Southern Hemisphere, but consists of three species only, which occur on the coasts of New Zealand, and are valued as food-fishes.

Other genera, with narrow unsymmetrical mouth, in which the upper eye is not in advance of the lower, and which have pectoral fins, are Parophrys, Psammodiscus, Ammotretis, Peltorhamphus, Nematops, Læops, and Poecilopsetta.

Solea.—Eyes on the right side, the upper being more or less in advance of the lower. Cleft of the mouth narrow, twisted round to the left side. Villiform teeth on the blind side only; vomerine or palatine teeth none. The dorsal fin commences on the snout, and is not confluent with the caudal. Scales very small, ctenoid; lateral line straight.

“Soles” are numerously represented in all suitable localities within the temperate and tropical zones, with the exception of the southern parts of the southern temperate zone, in which they are absent. Some enter or live in fresh water. Nearly forty species are known. British are S. vulgaris, the common “Sole;” S. aurantiaca, the “Lemon-sole,” which is rather a southern species, and inhabits, on the south coast of England, deeper water than the common Sole; S. variegata, the “Banded Sole,” with very small pectoral fins; and S. minuta, the “Dwarf-Sole.”—Allied to Solea are Pardachirus and Liachirus from the Indian coasts.

Synaptura.—Eyes on the right side, the upper in advance of the lower. Cleft of the mouth narrow, twisted round to the left side; minute teeth on the left side only. Vertical fins confluent. Scales small, ctenoid; lateral line straight.

Twenty species; with the exception of two from the Mediterranean and coast of Portugal, all belong to the fauna of the Indian Ocean.—Closely allied is Aesopia.

Gymnachirus.—Mouth very small, toothless. Scales none, lateral line straight. Eyes on the right side. The dorsal fin commences on the snout; caudal free. Pectorals rudimentary or entirely absent.

Two species from the Tropical Atlantic.

Cynoglossus.—Eyes on the left side; pectorals none; vertical fins confluent. Scales ctenoid; lateral line on the left side double or triple; upper part of the snout produced backwards into a hook; mouth unsymmetrical, rather narrow. Teeth minute, on the right side only.

Abundant in the Indian seas, and especially on the flat sandy shores of China. About thirty-five species are known, which rarely exceed a length of eighteen inches. They are easily recognised by their long narrow shape (which has been compared to a dog’s tongue) and the peculiar form of their snout.

To complete the list of Pleuronectoid genera, the following have to be mentioned: Soleotalpa and Apionichthys, Soles with rudimentary eyes; Ammopleurops, Aphoristia, and Plagusia, which are closely allied to Cynoglossus, the latter genus having the lips provided with tentacles.

Fourth Order—Physostomi.

All the fin-rays articulated, only the first of the dorsal and pectoral fins is sometimes ossified. Ventral fins, if present, abdominal, without spine. Air-bladder, if present, with a pneumatic duct (except in Scombresocidæ).

First Family—Siluridæ.

Skin naked or with osseous scutes, but without scales. Barbels always present; maxillary bone rudimentary, almost always forming a support to a maxillary barbel. Margin of the upper jaw formed by the intermaxillaries only. Suboperculum absent. Air-bladder generally present, communicating with the organ of hearing by means of the auditory ossicles. Adipose fin present or absent.

A large family, represented by numerous genera, which exhibit a great variety of form and structure of the fins; they inhabit the fresh waters of all the temperate and tropical regions; a few enter the sea but keep near the coast. The first appearance of Siluroids is indicated by some fossil remains in tertiary deposits of the highlands of Padang in Sumatra, where Pseudeutropius and Bagarius, types well represented in the living Indian fauna, have been found. Also in North America spines referable to Cat-fishes have been found in tertiary formations.

The skeleton of the typical Siluroids shows many peculiarities. The cranial cavity is not membranous on the sides, but closed as in the Cyprinidæ, by the orbitosphenoids and the ethmoid that unite with the prefrontals, carrying forward the cranial cavity to the nasal bone, without leaving a membranous septum between the orbits. But the supraoccipital is greatly developed, and in many the post-temporal is united by suture to the sides of the cranium. In numerous members of the family the skull is enlarged posteriorly, by dermal ossifications, to form a kind of helmet which spreads over the nape; the lateral angles of this production are formed by the suprascapulæ, augmented and fixed by suture, and the median part is the extension of the supraoccipital, which is generally very large, is connected anteriorly with the frontal, and passing backwards between the postfrontals, the parietals, the mastoids, and the suprascapulæ, goes past them all on to the nape. The mastoids interpose between the postfrontals and the parietals, so as to come in contact with the supraoccipital, and the parietals but little developed are pressed to the back part of the cranium, and in some instances wholly disappear.

The suprascapula most frequently unites to the mastoid by an immovable suture, which includes the parietal when that bone is present, and extends even to the supraoccipital. It gives out besides two processes, one of them resting on the exoccipital and basi-occipital, or wedging itself between them, and the other going to the first vertebra; sometimes a plate from the exoccipital supports the same vertebra. This vertebra, though it presents a pretty continuous centrum beneath, is in reality composed of three or four coalescent vertebræ, as we ascertain by its diapophyses, by the circular elevations of the neural canal, and by the holes for the exit of the pairs of spinal nerves. There is great variety in the development of the various processes of the bones we have mentioned, and there is no less in the magnitude and connections of the first three interneurals.

In general in the species which have a strong dorsal spine the second and third interneurals unite to form a single plate, the “buckler;” the great spine is articulated to the third interneural, and there is only the vestige of a spine on the second interneural in form of a small oval bone, forked below, whose function is to act as a bolt or fulcrum to the great spine when the fish wishes to use it as an offensive weapon. The great spine itself is joined by a ring to a second spine, which belongs to the third interneural. This articulation by ring exists in Lophius and a few other fishes not of this family.

The first interneural does not carry a ray, and it varies much in the species whose helmet is continuous with the buckler, as in many of the Bagri and Pimelodi. In these cases the supraoccipital, extending backwards, conceals the first interneural, passing over it to touch with its point the buckler formed by the second and third interneurals. In other instances, as in Synodontis and Auchenipterus, the supraoccipital and second interneural, forking and expanding, inclose and join themselves to the first interneural, but leave a larger or smaller space in the middle of the nuchal armour which they contribute to form. When the point of the supraoccipital does not reach quite to the second interneural, the first interneural remains free from connection, and occasionally shows as a narrow plate interposed between the other two; in such a case the helmet is not continuous with the buckler.

The neural spines of the coalescent centra, which form the apparently single first vertebra, concur also in sustaining the nuchal plate-armour and the first great dorsal spine. They carry the interneurals, are joined to them by suture, and one of them is often inclined towards the occiput to assist in sustaining the head; in fact, this part of the skeleton is constructed to give firm mutual support.

The shoulder-girdle of the Siluroids is also formed to give resistance to the strong weapon with which it is frequently armed. The post-temporal, as we have said above, is often united by suture to the cranium, and it obtains support below by one or two processes that are fixed on the basioccipitals and on the diapophysis of the first vertebra.

In most osseous fishes the clavicle completes the lower key of the scapular arch in joining its fellow by suture or synchondrosis without the intervention of the coracoid; but in the Siluroids the coracoid descends to take part in this joint, and sometimes even to occupy the half of the suture, which is not unfrequently constructed of very deep interlocking serratures. The solidity of this base of the pectoral spine is further augmented by the intimate union of the coracoid and scapula, which often extends to junction by suture, or even to coalescence; and these bones, moreover, give off two bony arches—the first a slender one, arising from the salient edge of the coracoid near the pectoral fin, and going to the interior face of the scapular that is applied to the interior surface of the ascending branch of the clavicle; the second and broader supplementary arch is often perforated by a large hole; it also emanates from the same salient edge of the radius, but proceeds in opposite direction to the inferior edge of the clavicle, a little before the insertion of the pectoral spine. The two arches give attachments to the muscles that move this spine; in the Synodontes and many Bagri the upper arch remains in a cartilaginous or ligamentous condition, while in Malapterurus it is the lower arch that does not ossify, but both are fully formed in the Siluri and many other Siluroids more closely allied to that typical genus. The postclavicle is also wanting in the Siluroids. The pterygoid and entopterygoid are reduced to a single bone, the symplectic is wholly wanting, and the palatine is merely a slender cylindrical bone. The sub-operculum is likewise constantly absent in all the Siluroids.

The great number of different generic types has necessitated a further division of this family into eight subdivisions:

I. Siluridæ Homalopteræ.—The dorsal and anal fins are very long, nearly equal in extent to the corresponding parts of the vertebral column.

a. Clariina.

Clarias.—Dorsal fin extending from the neck to the caudal, without adipose division. Cleft of the mouth transverse, anterior, of moderate width; barbels eight; one pair of nasal, one of maxillary, and two pairs of mandibulary barbels. Eyes small. Head depressed; its upper and lateral parts are osseous, or covered with only a very thin skin. A dendritic accessory branchial organ is attached to the convex side of the second and fourth branchial arches, and received in a cavity behind the gill-cavity proper. Ventrals six-rayed; only the pectoral has a pungent spine. Body eel-like.

Twenty species from Africa, the East Indies, and the intermediate parts of Asia; some attain to a length of six feet. They inhabit muddy and marshy waters; the physiological function of the accessory branchial organ is not known. Its skeleton is formed by a soft cartilaginous substance covered by mucous membrane, in which the vessels are imbedded. The vessels arise from branchial arteries, and return the blood into branchial veins. The vernacular name of the Nilotic species is “Carmoot.”

Heterobranchus differs from Clarias only in the structure of the dorsal fin, the posterior portion of which is adipose.

The geographical range of this genus is not quite co-extensive with that of Clarias, inasmuch as it is limited to Africa and the East-Indian Archipelago. Six species.

b. Plotosina.

Plotosus.—A short dorsal fin in front, with a pungent spine; a second long dorsal coalesces with the caudal and anal. Vomerine teeth molar-like. Barbels eight or ten; one immediately before the posterior nostril, which is remote from the anterior, the latter being quite in front of the snout. Cleft of the mouth transverse. Eyes small. The gill-membranes are not confluent with the skin of the isthmus. Ventral fins many-rayed. Head depressed; body elongate.

Fig. 258.—Mouth of Cnidoglanis megastoma, Australia.

Three species are known from brackish waters of the Indian Ocean freely entering the sea. Plotosus anguillaris is distinguished by two white longitudinal bands, and is one of the most generally distributed and common Indian fishes.—Copidoglanis and Cnidoglanis are two very closely allied forms, chiefly from rivers and brackish waters of Australia. None of these Siluroids attain to a considerable size. Chaca, from the East Indies, belongs likewise to this sub-family.

Fig. 259.—Cnidoglanis microcephalus.

II. Siluridæ Heteropteræ.—The rayed dorsal fin is very little developed, and, if it is present, it belongs to the abdominal portion of the vertebral column; the adipose fin is exceedingly small or absent. The extent of the anal is not much inferior to that of the caudal vertebral column. The gill-membranes overlap the isthmus, remaining more or less separate: Silurina.

Saccobranchus.—Adipose fin none; dorsal very short, without pungent spine, placed above the ventrals. Cleft of the mouth transverse, anterior, of moderate width; barbels eight. Eyes rather small. The upper and lateral parts of the head osseous or covered with a very thin skin. Gill-cavity with an accessory posterior sac, extending backwards between the muscles along each side of the abdominal and caudal portions of the vertebral column. Ventrals six-rayed.

Small fishes from East Indian rivers; four species are known. The lung-like extension of the branchial cavity receives water, and is surrounded by contractile transverse muscular fibres by which the water is expelled at intervals. The vessels of the sac take their origin in the last branchial artery, and pass into the aorta.

Silurus.—No adipose fin; one very short dorsal, without pungent spine. Barbels four or six, one to each maxillary, and one or two to each mandible. Nostrils remote from each other. Head and body covered with soft skin. The eye is situated above the level of the angle of the mouth. The dorsal fin is anterior to the ventrals which are composed of more than eight rays. Caudal rounded.

This genus, of which five species are known, inhabits the temperate parts of Europe and Asia. The species which has given the name to the whole family, is the “Wels” of the Germans, Silurus glanis. It is found in the fresh waters east of the Rhine, and is, besides the Sturgeons, the largest of European Freshwater-fishes, and the only species of this family which occurs in Europe. Barbels six. It attains to a weight of 300 or 400 lbs., and the flesh, especially of smaller specimens, is firm, flaky, and well flavoured. Aristotle described it under the name of Glanis. Its former occurrence in Scotland has justly been denied. In China it is represented by a similar species, S. asotus, which, however, has four barbels only.

Fig. 260.—The “Wels,” Siluris glanis.

This sub-family is well represented by various other genera in the fresh waters of the African as well as Indian region. African genera are Schilbe and Eutropius; East Indian: Silurichthys, Wallago, Belodontichthys, Eutropiichthys, Cryptopterus, Callichrous, Hemisilurus, Siluranodon, Ailia, Schilbichthys, Lais, Pseudeutropius, Pangasius, Helicophagus, and Silondia.

III. Siluridæ Anomalopteræ.—Dorsal and adipose fins very short, the former belonging to the caudal vertebral column; anal very long. Ventrals in front of the dorsal. Gill-membranes entirely separate, overlapping the isthmus: (Hypophthalmina.)

Hypophthalmus.—Dorsal fin with seven rays, the first of which is slightly spinous. The lower jaw is rather the longer. Barbels six, those of the mandible long. No teeth; intermaxillaries very feeble. Head covered with skin. Eye of moderate size, situated behind and below the angle of the mouth. Ventrals small, six-rayed.

Four species from tropical America. The second genus of this sub-family is Helogenes from the Essequibo.

IV. Siluridæ Proteropteræ.—The rayed dorsal fin is always present, short, with not more than twelve short rays, and belongs to the abdominal portion of the vertebral column, being placed in advance of the ventrals. The adipose fin is always present and well developed, although frequently short. The extent of the anal is much inferior to that of the caudal vertebral column. The gill-membranes are not confluent with the skin of the isthmus, their posterior margin always remaining free even if they are united with each other. Whenever the nasal barbel is present it belongs to the posterior nostril.

a. Bagrina.

Bagrus.—Adipose fin long; a short dorsal with a pungent spine and nine or ten soft rays; anal fin short, with less than twenty rays. Barbels eight. The anterior and posterior nostrils are remote from each other, the posterior being provided with a barbel. Teeth on the palate in a continuous band. Eyes with a free orbital margin. Caudal forked; ventrals six-rayed.

This genus consists of two species only, common in the Nile, viz. the “Bayad,” B. bayad, and B. docmac. Both grow to a large size, exceeding a length of five feet, and are eaten. Chrysichthys and Clarotes are two other Siluroid genera from African rivers, closely allied to Bagrus. Similar Siluroids are common in the East Indies, and have been referred to the following genera: Macrones, Pseudobagrus, Liocassis, Bagroides, Bagrichthys, Rita, Acrochordonichthys, Akysis.

b. Amiurina.

Amiurus.—Adipose fin of moderate length; a short dorsal with a pungent spine and six soft rays; anal fin of moderate length. Barbels eight. The anterior and posterior nostrils are remote from each other, the posterior being provided with a barbel. Palate edentulous. Head covered with skin above. Ventrals eight-rayed.

The “Cat-fishes” of North America, of which about a dozen different species are known. One species occurs in China. Allied, but smaller forms are Hopladelus and Noturus, likewise from North America.

c. Pimelodina.

Platystoma.—Adipose fin of moderate length; a short dorsal fin with a pungent spine and six or seven soft rays; anal fin rather short. Snout very long, spatulate, with the upper jaw more or less projecting; the upper surface of the head not covered by the skin. Barbels six; the anterior and posterior nostrils remote from each other, none with a barbel. Palate toothed. Caudal forked; ventrals six-rayed, inserted behind the dorsal.

Twelve species from South America, some attaining a length of six feet, the majority being ornamented with deep-black spots or bands. Allied genera from South America, likewise distinguished by a long spatulate snout, are Sorubim, Hemisorubim, and Platystomatichthys, whilst Phractocephalus, Piramutana, Platynematichthys, Piratinga, Bagropsis, and Sciades, have a snout of ordinary length. The barbels of some are of extraordinary length, and not rarely dilated and band-like.

Pimelodus.—Adipose fin well developed; dorsal fin short, with a more or less pungent spine and six rays; anal fin short. Barbels six, cylindrical or slightly compressed, none of them belonging to either of the nostrils, which are remote from each other. Palate edentulous. Ventrals six-rayed, inserted behind the dorsal.

Of all South American genera this is represented by the greatest number of species, more than forty being well characterised; they differ chiefly with regard to the length of the adipose fin and barbels, and the strength of the dorsal spine. Singularly, two species (P. platychir and P. balayi), are found in West Africa. The majority are of but moderate size and plain coloration.—Allied South American genera (also without teeth on the palate), are Pirinampus, Conorhynchus, Notoglanis, Callophysus, Lophiosilurus.

Auchenoglanis.—Adipose fin rather long, dorsal short, with a pungent spine and seven rays; anal short. Snout produced, pointed, with narrow mouth. Barbels six, none of which belongs to either of the nostrils, which are remote from each other. The teeth of each jaw form a pair of small elliptic patches which are longer than broad; palate edentulous. Eyes of moderate size. Ventrals six-rayed.

One species, Au. biscutatus, from the Nile, Senegal, and other West African rivers.

d. Ariina.

Arius.—Adipose fin of moderate length or short; a short dorsal fin with a pungent spine and seven soft rays; anal fin rather short. Head osseous above; barbels six, four at the mandible, none at either of the nostrils which are close together. Eyes with a free orbital margin. Caudal fin forked; ventrals six-rayed, behind the dorsal.

Of all Siluroid genera this has the greatest number of species (about seventy), and the widest distribution, being represented in almost all tropical countries which are drained by large rivers; some of the species prefer brackish to fresh water, and a few enter the sea, but keep near to the coast. Some of the species are of small size, whilst others exceed a length of five feet. The extent of the armature of the neck and the dentition vary much in the different species, and affords two of the principal characters by which the species are separated.—The following genera are allied to Arius, Galeichthys from South Africa; Genidens and Paradiplomystax from Brazil; Diplomystax from Chile; Aelurichthys from Central and South America; Hemipimelodus, Ketengus, Osteogeniosus, and Batrachocephalus from the East Indies; and Atopochilus from West Africa.

Fig. 261.—Arius australis, from Queensland.

e. Bagariina.

Bagarius.—Adipose fin rather short; a short dorsal with one spine and six rays; anal fin of moderate length. Barbels eight, of which one pair stands between the anterior and posterior nostrils which are close together. Head naked above. Caudal fin deeply forked; ventrals rays six. Thorax without longitudinal plaits of the skin.

A large Siluroid (B. bagarius) from rivers of India and Java; exceeding a length of six feet.

Fig. 262.—Euglyptosternum coum, thoracic adhesive apparatus.

Euglyptosternum.—Adipose fin of moderate length; a short dorsal with a pungent spine and six rays; anal fin short. Barbels eight, of which one pair is placed between the anterior and posterior nostrils which are close together. Teeth on the palate villiform, in two separate patches. Eyes small, below the skin. Caudal forked; ventral rays six. Pectorals horizontal, with a thoracic adhesive apparatus between, which is formed by longitudinal plaits of the skin.

This fish (Eu. coum) inhabits the river Coic in Syria, and is about twelve inches long. The plaited structure on the thorax probably increases the capability of the fish of maintaining its position in the rapid current of the stream, a function which appears to be chiefly performed by the horizontally expanded pectoral fins. A similar structure is found in Glyptosternum, a genus represented by eight species in mountain streams of the East Indies, and differing from the Syrian species in lacking the teeth on the palate.

V. Siluridæ Stenobranchiæ.—The rayed dorsal fin is short, if present, belonging to the abdominal portion of the vertebral column, the ventrals being inserted behind it (except in Rhinoglanis). The gill-membranes are confluent with the skin of the isthmus.

a. Doradina.

Some of the genera have no bony shields along the lateral line, and a small adipose fin or none whatever; all of these are South American—Ageniosus, Tetranematichthys, Euanemus, Auchenipterus, Glanidium, Centromochlus, Trachelyopterus, Cetopsis, and Astrophysus.

Others have a series of bony scutes along the middle of the side; they form the genus Doras with two closely allied forms, Oxydoras and Rhinodoras. Some twenty-five species are known, all from rivers of tropical America, flowing into the Atlantic. These fishes have excited attention by their habit of travelling, during the dry season, from a piece of water about to dry up, in quest of a pond of greater capacity. These journeys are occasionally of such a length that the fish spends whole nights on the way, and the bands of scaly travellers are sometimes so large that the Indians who happen to meet them, fill many baskets of the prey thus placed in their hands. The Indians supposed that the fish carry a supply of water with them, but they have no special organs, and can only do so by closing the gill-openings, or by retaining a little water between the plates of their bodies, as Hancock supposes. The same naturalist adds that they make regular nests, in which they cover up their eggs with care and defend them, male and female uniting in this parental duty until the eggs are hatched. The nest is constructed at the beginning of the rainy season, of leaves, and is sometimes placed in a hole scooped out in the beach.

Finally, in the last genus, the lateral scutes are likewise absent, viz. in

Synodontis.—The adipose fin is of moderate length or rather long; the dorsal fin has a very strong spine and seven soft rays. The teeth in the lower jaw are movable, long, very thin at the base, and with a slightly-dilated brown apex. Mouth small. Barbels six, more or less fringed with a membrane or with filaments. Neck with broad dermal bones.

Synodontis is characteristic of the fauna of tropical Africa, where it is represented by fifteen species. Several occur in the Nile, and are known by the vernacular name “Schal.” Some attain a length of two feet. The species figured is from West Africa, and characterised by its long upper jaw.

Fig. 263.—Synodontis xiphias.

b. Rhinoglanina.

Rhinoglanis.—Two dorsal fins, both composed of rays, the first with a strong spine; anal rather short. Barbels six; anterior and posterior nostrils close together, the posterior very large, open. Neck with broad dermal bones. Ventrals with seven rays, inserted below the posterior rays of the first dorsal fin.

This Siluroid is known from a single example only one and a half inches long, obtained at Gondokoro on the Upper Nile. Callomystax represents this type in the Ganges and Indus.

c. Malapterurina.

Malapterurus.—One dorsal fin only, which is adipose and situated before the caudal; anal of moderate length or short; caudal rounded; ventrals six-rayed, inserted somewhat behind the middle of the body; pectorals without pungent spine. Barbels six: one to each maxillary and two on each side of the mandible. The anterior and posterior nostrils are remote from each other. No teeth on the palate. The entire head and body covered with soft skin. Eyes small. Gill-opening very narrow, reduced to a slit before the pectoral.

The “Electric Cat- or Sheath-fishes” are not uncommon in the fresh waters of tropical Africa; three species have been described, of which M. electricus occurs in the Nile; they grow to a length of about four feet. Although the first dorsal fin is absent, its position (if it had been developed) is indicated by a rudimentary interneural spine, which rests in the cleft of the neural process of the first vertebra. The electric organ extends over the whole body, but is thickest on the abdomen; it lies between two aponeurotic membranes, below the skin, and consists of rhomboidal cells which contain a rather firm gelatinous substance. The electric nerve takes its origin from the spinal chord, does not enter into connection with ganglia, and consists of a single enormously-strong primitive fibre, which distributes its branches in the electric organ.

Fig. 264.—Malapterurus electricus.

VI. Siluridæ Proteropodes.—The rayed dorsal fin is always present and rather short; the ventrals are inserted below (very rarely in front of) the dorsal. The gill-membranes are confluent with the skin of the isthmus, the gill-opening being reduced to a short slit. Pectorals and ventrals horizontal. Vent before, or not much behind, the middle of the length of the body.

a. Hypostomatina.

Stygogenes.—Adipose fin short; dorsal and anal short; the outer fin-rays somewhat thickened and rough; palate toothless; cleft of the mouth of moderate width, with a maxillary barbel on each side; a short broad flap on each side between the nostrils, which are close together. Lower lip very broad, pendent. Eyes small, covered with transparent skin. Head covered with soft skin. Ventrals six-rayed.

These small Siluroids, which are called “Preñadillas” by the natives, together with the allied Arges, Brontes, and Astroplebus, have received some notoriety through Humboldt’s accounts, who adopted the popular belief that they live in subterranean waters within the bowels of the active volcanoes of the Andes, and are ejected with streams of mud and water during eruptions. Humboldt himself considers it very singular that they are not cooked and destroyed whilst they are vomited forth from craters or other openings. The explanation of their appearance during volcanic eruptions is, that they abound in the numerous lakes and torrents of the Andes, that they are killed by the sulphuretted gases escaping during an eruption, and swept down by the torrents of water issuing from the volcano.

Callichthys.—Adipose fin short, supported anteriorly by a short movable spine; dorsal with a feeble spine and seven or eight rays; anal short. Teeth minute or entirely absent; cleft of the mouth rather narrow, with a pair of maxillary barbels on each side, which are united at the base. Eyes small. Head covered with osseous plates; body wholly protected by two series of large imbricate shields on each side. Ventrals six-rayed.

Twelve species of this genus are known; they are small, and similarly distributed as Doras, with which they have much in common as regards their mode of life. They likewise are able to travel over land, and construct nests for their ova.

Fig. 265.—Callichthys armatus, from the Upper Amazon. Natural size.

Chætostomus.—A short adipose fin, supported anteriorly by a short, compressed, curved spine; dorsal fin of moderate length, with from eight to ten rays, the first of which is simple; anal fin short; ventral six-rayed; pectoral with a strong spine. Head and body completely cuirassed, the lower parts being sometimes naked; body rather short, with four or five longitudinal series of large imbricate scutes on each side; tail not depressed. Snout produced, obtuse in front; mouth inferior, transverse, with a single series of generally very fine bent teeth in both jaws. Interoperculum very movable and armed with erectile spines.

This genus, with the allied Plecostomus, Liposarcus, Pterygoplichthys, Rhinelepis, Acanthicus, and Xenomystus, is well represented in the fresh waters of South America, whence about sixty species are known. The majority do not exceed a length of twelve inches, but some attain to more than double that size. In some of the species the male is provided with long bristles round the margin of the snout and interoperculum.

Fig. 266.—Upper and Lower side of the head of Chætostomus heteracanthus, Upper Amazons.

Hypoptopoma.—Differing from Chætostomus in the peculiar formation of the head, which is depressed, spatulate, the eyes being on the lateral edge of the head. The movable gill-covers are reduced to two bones, neither of which is armed, viz.—the operculum small and placed as in Chætostomus, and a second, larger one, separated from the eye by the narrow sub-orbital ring, and placed at the lower side of the head.

Fig. 267.—Hypoptopoma thoracatum, Upper Amazons. Natural size.

Loricaria.—One short dorsal fin; anal short; the outer ray of each fin thickened, but flexible. Head depressed, with the snout more or less produced and spatulate. Mouth situated at the lower side of the snout, remote from its extremity, transverse, surrounded by broad labial folds which are sometimes fringed; a short barbel at each corner of the mouth. Teeth in the jaws small, bent, with a dilated, notched apex, in a single series, sometimes absent. Head and body cuirassed; tail depressed, long; eye rather small or of moderate size.

Fig. 268.—Loricaria lanceolate, Upper Amazons. Natural size.

Small fishes from rivers of tropical America; about twenty-six species are known. The male of some species has a bearded or bristly snout.

Acestra differs from Loricaria in having the snout much prolonged.

Sisor.—Head depressed, spatulate; trunk depressed; tail long and thin. One short dorsal fin; anal short; ventrals seven-rayed. Head partially osseous, rough; a series of bony plates along the median line of the back; lateral line rough. Eyes very small. Mouth inferior, small, transverse, with barbels; teeth none.

A single species, S. rhabdophorus, from rivers of northern Bengal. Allied to this genus is Erethistes from Assam.

Pseudecheneis.—Adipose fin of moderate length; a short dorsal with one spine and six rays; anal fin rather short. Barbels eight. Mouth small, inferior. Head depressed, covered with soft skin above; eyes small, superior. Caudal fin forked; pectorals horizontal, with a thoracic adhesive apparatus between, formed by transverse plaits of the skin. Ventrals six-rayed.

A very small species, inhabiting the mountain-streams of Khassya; by means of the adhesive apparatus it is enabled to hold on to stones, thus preventing the current from sweeping it away. Exostoma is a similar small Siluroid from Indian mountain-streams, but without the thoracic apparatus; probably its mouth performs the same function.

b. Aspredinina.

Aspredo.—Adipose fin none; dorsal short, without pungent spine; anal very long, but not united with the caudal. Head broad, much depressed; tail very long and slender. Barbels not less than six, one of which is attached to each intermaxillary; none at the nostrils. Eyes very small. Head covered with soft skin; the anterior and posterior nostrils are remote from each other. Ventrals six-rayed.

Six species are known from Guyana; the largest grows to a length of about eighteen inches. The remarkable mode of taking care of their ova has been noticed above (p. 161, Fig. [72]). Bunocephalus, Bunocephalichthys, and Harttia, from tropical America, are other genera of this sub-family which remain to be mentioned.

VII. Siluridæ Opisthopteræ.—The rayed dorsal fin is always present, short, and placed above or behind the middle of the length of the body, above or behind the ventrals which, however, are sometimes absent; anal short. Nostrils remote from each other; if a nasal barbel is present, it belongs to the anterior nostril. Lower lip not reverted. The gill-membranes are not confluent with the skin of the isthmus: Nematogenyina and Trichomycterina.

The genera Heptapterus, Nematogenys, Trichomycterus, Eremophilus, and Pariodon, belong to this sub-family. They are small South American Siluroids, the majority of which inhabit waters at high altitudes, up to 14,000 feet above the level of the sea. In the Andes they replace the Loaches of the Northern Hemisphere, which they resemble in appearance and habits, and even in coloration, offering a striking example of the fact that similar forms of animals are produced under similar external physical conditions.

VIII. Siluridæ Branchicolæ.—The rayed dorsal fin is present, short, and placed behind the ventrals; anal short. Vent far behind the middle of the length of the body. Gill-membranes confluent with the skin of the isthmus.

Stegophilus and Vandellia, two genera from South America, comprising the smallest and least developed Siluroids. Their body is narrow, cylindrical, and elongate; a small barbel at each maxillary; the operculum and interoperculum are armed with short stiff spines. The natives of Brazil accuse these fishes of entering and ascending the urethra of persons while bathing, causing inflammation and sometimes death. This requires confirmation, but there is no doubt that they live parasitically in the gill-cavity of larger fishes (Platystoma), but probably they enter these cavities only for places of safety, without drawing any nourishment from their host.

Second Family—Scopelidæ.

Body naked or scaly. Margin of the upper jaw formed by the intermaxillary only; opercular apparatus sometimes incompletely developed. Barbels none. Gill-opening very wide; pseudobranchiæ well developed. Air-bladder none. Adipose fin present. The eggs are enclosed in the sacs of the ovary, and excluded by oviducts. Pyloric appendages few in number or absent. Intestinal tract very short.

Exclusively marine, the majority being either pelagic or deep-sea forms. Of fossil remains the following have been referred to this family:—Osmeroides, from Mount Lebanon, which others believe to be a marine salmonoid; Hemisaurida, from Comen, allied to Saurus; Parascopelus and Anapterus, from the miocene of Licata, the latter genus allied to Paralepis.

Saurus (inclus. Saurida).—Body sub-cylindrical, rather elongate, covered with scales of moderate size; head oblong; cleft of the mouth very wide; intermaxillary very long, styliform, tapering; maxillary thin, long, closely adherent to the intermaxillary. Teeth card-like, some being elongate, slender; all can be laid downwards and inwards. Teeth on the tongue, and palatine bones. Eye of moderate size. Pectorals short; ventrals eight- or nine-rayed, inserted in advance of the dorsal, not far behind the pectorals. Dorsal fin nearly in the middle of the length of the body, with thirteen or less rays; adipose fin small; anal short or of moderate length; caudal forked.

Fifteen species of small size, from the shores of the tropical and sub-tropical zones. The species figured on p. 42, Fig. [5], occurs on the north-west coast of Australia and in Japan.

Bathysaurus.—Shape of the body similar to that of Saurus, sub-cylindrical, elongate, covered with small scales. Head depressed, with the snout produced, flat above. Cleft of the mouth very wide, with the lower jaw projecting; intermaxillary very long, styliform, tapering, not movable. Teeth in the jaws, in broad bands, not covered by lips, curved, unequal in size and barbed at the end. A series of similar teeth runs along the whole length of each side of the palate. Eye of moderate size, lateral. Pectoral of moderate length. Ventral eight-rayed, inserted immediately behind the pectoral. Dorsal fin in the middle of the length of the body, with about eighteen rays. Adipose fin absent or present. Anal of moderate length. Caudal emarginate.

Deep-sea fishes, obtained in the Pacific at depths varying from 1100 to 2400 fathoms. The largest example is twenty inches long. Two species.

Bathypterois.—Shape of the body like that of an Aulopus. Head of moderate size, depressed in front, with the snout projecting, the large mandible very prominent beyond the upper jaw. Cleft of the mouth wide; maxillary developed, very movable, much dilated behind. Teeth in narrow villiform bands in the jaws. On each side of the broad vomer a small patch of similar teeth; none on the palatines or on the tongue. Eye very small. Scales cycloid, adherent, of moderate size. Rays of the pectoral fin much elongated, some of the upper being separate from the rest, and forming a distinct division. Ventrals abdominal, with the outer rays prolonged, eight-rayed. Dorsal fin inserted in the middle of the body, above or immediately behind the root of the ventral, of moderate length. Adipose fin present or absent. Anal short. Caudal forked.

This very singular form is one of the discoveries of the “Challenger;” it is widely distributed over the seas of the Southern Hemisphere, in depths varying from 520 to 2600 fathoms. The elongate pectoral rays are most probably organs of touch. Four species were discovered, the largest specimen being thirteen inches long.

Harpodon.—Body elongate, covered with very thin, diaphanous, deciduous scales. Head thick, with very short snout; its bones are very soft, and the superficial ones are modified into wide muciferous cavities; the lateral canal of the body is also very wide, and a pair of pores corresponds to each scale of the lateral line, one being above, the other below the scale. Cleft of the mouth very wide; intermaxillary very long, styliform, tapering; maxillary absent. Teeth card-like, recurved, unequal in size; the largest are in the lower jaw, and provided with a single barb at the posterior margin of the point. Eye small. Ventral fins long, nine-rayed, inserted below the anterior dorsal rays; dorsal fin in the middle of the length of the body; adipose fin small; anal of moderate length; caudal fin three-lobed, the lateral line being continued along the central lobe. Centre of the vertebræ open in the middle.

Two species only are known of this singular genus; both are evidently inhabitants of considerable depths, and periodically come nearer to the surface. One (H. nehereus) is well known in the East Indies, being of excellent flavour. When newly taken its body is brilliantly phosphorescent. When salted and dry it is known under the names of “Bombay-ducks” or “Bummaloh,” and exported in large quantities from Bombay and the coast of Malabar. The second species (H. microchir) exceeds the other in length, and has been found in the sea off Japan.

Fig. 269.—Scopelus boops.

Scopelus.—Body oblong, more or less compressed, covered with large scales. Series of phosphorescent spots run along the lower side of the body, and a similar glandular substance sometimes occupies the front of the snout and the back of the tail. Cleft of the mouth very wide. Intermaxillary very long, styliform, tapering; maxillary well developed. Teeth villiform. Eye large. Ventrals eight-rayed, inserted immediately in front of or below the anterior dorsal rays. Dorsal fin nearly in the middle of the length of the body; adipose fin small; anal generally long; caudal forked. Branchiostegals from eight to ten.

The fishes of this genus are small, of truly pelagic habits, and distributed over all the temperate and tropical seas; they are so numerous that the surface-net, when used during a night of moderate weather, scarcely ever fails to enclose some specimens. They come to the surface at night only; during the day and in very rough weather they descend to depths where they are safe from sunlight or the agitation of the water. Some species never rise to the surface; indeed, Scopeli have been brought up in the dredge from almost any depth to 2500 fathoms. Thirty species are known. Gymnoscopelus differs from Scopelus in lacking scales.

Ipnops.—Body elongate, sub-cylindrical, covered with large, thin, deciduous scales, and without phosphorescent organs. Head depressed, with broad, long, spatulate snout, the whole upper surface of which is occupied by a most peculiar organ of vision (or luminosity), longitudinally divided in two symmetrical halves. Bones of the head well ossified. Mouth wide, with the lower jaw projecting; maxillary dilated behind. Both jaws with narrow bands of villiform teeth; palate toothless. Pectoral and ventral fins well developed, and, owing to the shortness of the trunk, close together. Dorsal fin at a short distance behind the vent; adipose fin none; anal fin moderately long; caudal subtruncated. Pseudobranchiæ none.

This singular genus, one of the “Challenger” discoveries, is known from four examples, obtained at depths varying between 1600 and 2150 fathoms, off the coast of Brazil, near Tristan d’Acunha and north of Celebes. All belong to one species, I. murrayi. The eye seems to have lost its function of vision and assumed that of producing light. The specimens are from 4 to 5½ inches long.

Paralepis.—Head and body elongate, compressed, covered with deciduous scales. Cleft of the mouth very wide; maxillary developed, closely adherent to the intermaxillary. Teeth in a single series, unequal in size. Eye large. Ventrals small, inserted opposite or nearly opposite the dorsal. Dorsal fin short, on the hinder part of the body; adipose fin small; anal elongate, occupying the end of the tail; caudal emarginate.

Three species; small pelagic fishes from the Mediterranean and Atlantic.—Sudis, from the Mediterranean, has a dentition slightly different from that of Paralepis.

Plagyodus.—Body elongate, compressed, scaleless; snout much produced, with very wide cleft of the mouth. Intermaxillary very long and slender; maxillary thin, immovable. Teeth in the jaws and of the palate very unequal in size, the majority pointed and sharp, some very large and lanceolate. Eye large. Pectoral and ventral fins well developed; the rayed dorsal fin occupies the whole length of the back from the occiput to opposite the anal fin; adipose and anal fins of moderate size. Caudal forked. Branchiostegals six or seven.

Fig. 270.—Plagyodus ferox.

This is one of the largest and most formidable deep-sea fishes. One species only is well known, P. ferox, from Madeira and the sea off Tasmania; other species have been noticed from Cuba and the North Pacific, but it is not evident in what respects they differ specifically from P. ferox. This fish grows to a length of six feet, and from the stomach of one example have been taken several Octopods, Crustaceans, Ascidians, a young Brama, twelve young Boar-fishes, a Horse-mackerel, and one young of its own species. The stomach is coecal; the commencement of the intestine has extremely thick walls, its inner surface being cellular, like the lung of a reptile; a pyloric appendage is absent. All the bones are extremely thin, light, and flexible, containing very little earthy matter; singular is the development of a system of abdominal ribs, symmetrically arranged on both sides, and extending the whole length of the abdomen. Perfect specimens are rarely obtained on account of the want of coherence of the muscular and osseous parts, caused by the diminution of pressure when the fish reaches the surface of the water. The exact depth at which Plagyodus lives is not known; probably it never rises above a depth of 300 fathoms.

The other less important genera belonging to this family are Aulopus, Chlorophthalmus, Scopelosaurus, Odontostomus, and Nannobrachium.

Fig. 271.—Pharyngeal bones and teeth of the Bream, Abramis brama.

Third Family—Cyprinidæ.

Body generally covered with scales; head naked. Margin of the upper jaw formed by the intermaxillaries. Belly rounded, or, if trenchant, without ossifications. No adipose fin. Stomach without blind sac. Pyloric appendages none. Mouth toothless; lower pharyngeal bones well developed, falciform, sub-parallel to the branchial arches, provided with teeth, which are arranged in one, two, or three series. Air-bladder large, divided into an anterior and posterior portion by a constriction, or into a right or left portion, enclosed in an osseous capsule. Ovarian sacs closed.

The family of “Carps” is the one most numerously represented in the fresh waters of the Old World and of North America. Also numerous fossil remains are found in tertiary freshwater-formations, as in the limestones of Oeningen and Steinheim, in the lignites of Bonn, Stöchen, Bilin, and Ménat, in the marl slates and carbonaceous shales of Licata in Sicily, and of Padang in Sumatra, in corresponding deposits of Idaho in North America. The majority can be referred to existing genera: Barbus, Thynnichthys, Gobio, Leuciscus, Tinca, Amblypharyngodon, Rhodeus, Cobitis, Acanthopsis, only a few showing characters different from those of living genera: Cyclurus, Hexapsephus, Mylocyprinus (tertiary of North America).

Most Carps feed on vegetable and animal substances; a few only are exclusive vegetable feeders. There is much less diversity of form and habits in this family than in the Siluroids; however, the genera are sufficiently numerous to demand a further subdivision of the family into groups.

I. Catostomina.—Pharyngeal teeth in a single series, exceedingly numerous and closely set. Dorsal fin elongate, opposite to the ventrals; anal short, or of moderate length. Barbels none.

These fishes are abundant in the lakes and rivers of North America, more than thirty species having been described, and many more named, by American ichthyologists. Two species are known from North-Eastern Asia. They are generally called “Suckers,” but their vernacular nomenclature is very arbitrary and confused. Some of the species which inhabit the large rivers and lakes grow to a length of three feet and a weight of fifteen pounds. The following genera may be distinguished:—Catostomus, “Suckers,” “Red-horses,” “Stone-rollers,” “White Mullets;” Moxostoma; Sclerognathus, “Buffaloes,” “Black Horses;” and Carpiodes, “Spear-fish,” “Sail-fish.”

II. Cyprinina.—Anal fin very short, with not more than five or six, exceptionally seven, branched rays. Dorsal fin opposite ventrals. Abdomen not compressed. Lateral line running along the median line of the tail. Mouth frequently with barbels, never more than four in number. Pharyngeal teeth generally in a triple series in the Old World genera; in a double or single series in the North American forms, which are small and feebly developed. Air-bladder present, without osseous covering.

Cyprinus.—Scales large. Dorsal fin long, with a more or less strong serrated osseous ray; anal short. Snout rounded, obtuse, mouth anterior, rather narrow. Pharyngeal teeth, 3. 1. 1.-1. 1. 3, molar-like. Barbels four.

Fig. 272.—The Carp, Cyprinus carpio.

The “Carp” (C. carpio, “Karpfen,” “La carpe,”) is originally a native of the East, and abounds in a wild state in China, where it has been domesticated for many centuries; thence it was transported to Germany and Sweden, and the year 1614 is assigned as the date of its first introduction into England. It delights in tranquil waters, preferring such as have a muddy bottom, and the surface partially shaded with plants. Its food consists of the larvæ of aquatic insects, minute testacea, worms, and the tender blades and shoots of plants. The leaves of lettuce, and other succulent plants of a similar kind, are said to be particularly agreeable to them, and to fatten them sooner than any other food. Although the Carp eats with great voracity when its supply of aliment is abundant, it can subsist for an astonishing length of time without nourishment. In the winter, when the Carps assemble in great numbers, and bury themselves among the mud and the roots of plants, they often remain for many months without eating. They can also be preserved alive for a considerable length of time out of the water, especially if care be taken to moisten them occasionally as they become dry. Advantage is often taken of this circumstance to transport them alive, by packing them among damp herbage or damp linen; and the operation is said to be unattended with any risk to the animal, especially if the precaution be taken to put a piece of bread in its mouth steeped in brandy!

The fecundity of these fishes is very great, and their numbers consequently would soon become excessive but for the many enemies by which their spawn is destroyed. No fewer than 700,000 eggs have been found in the ovaries of a single Carp, and that, too, by no means an individual of the largest size. Their growth is very rapid, more so perhaps than that of any other Freshwater fish, and the size which they sometimes attain is very considerable. In certain lakes in Germany individuals are occasionally taken weighing thirty or forty pounds; and Pallas relates that they occur in the Volga five feet in length, and even of greater weight than the examples just alluded to. The largest of which we have any account is that mentioned by Bloch, taken near Frankfort-on-the-Oder, which weighed seventy pounds, and measured nearly nine feet in length,—a statement the accuracy of which is very much open to doubt.

Like other domesticated animals the Carp is subject to variation; some individuals, especially when they have been bred under unfavourable circumstances, have a lean and low body; others are shorter and higher. Some have lost every trace of scales, and are called “Leather-carps;” others retain them along the lateral line and on the back only (“Spiegelkarpfen” of the Germans). Finally, in some are the fins much prolonged, as in certain varieties of the Gold-fish. Cross-breeds between the Carp and the Crucian Carp are of common occurrence. The Carp is much more esteemed as food in inland countries than in countries where the more delicate kinds of sea fishes can be obtained.

Carassius differs from Cyprinus in lacking barbels; its pharyngeal teeth are compressed, in a single series, 4–4.

Two well-known species belong to this genus. The “Crucian Carp” (C. carassius, “Karausche”) is generally distributed over Central and Northern Europe, and extends into Italy and Siberia. It inhabits stagnant waters only, and is so tenacious of life that it will survive a lengthened sojourn in the smallest pools, where, however, it remains stunted; whilst in favourable localities it attains to a length of twelve inches. It is much subject to variation of form; very lean examples are commonly called “Prussian Carps.” Its usefulness consists in keeping ponds clean from a super-abundance of vegetable growth, and in serving as food for other more esteemed fishes. The second species is the “Gold-fish,” Carassius auratus. It is of very common occurrence in a wild state in China and the warmer parts of Japan, being entirely similar in colour to the Crucian Carp. In a domesticated state it loses the black or brown chromatophors, and becomes of a golden-yellow colour; perfect Albinos are comparatively scarcer. Many varieties and monstrosities have been produced during the long period of its domestication; the variety most highly priced at present being the so-called “Telescope-fish,” of which a figure is annexed. The Gold-fish is said to have been first brought to England in the year 1691, and is now distributed over nearly all the civilised parts of the world.

Fig. 273.—Cyprinus auratus, var.

Catla.—Scales of moderate size. Dorsal fin without osseous ray, with more than nine branched rays, commencing nearly opposite to the ventrals. Snout broad, with the integuments very thin; there is no upper lip, the lower with a free continuous posterior margin. Symphysis of the mandibulary bones loose, with prominent tubercles. Mouth anterior. Barbels none. Gill-rakers very long, fine, and closely set. Pharyngeal teeth, 5. 3. 2.-2. 3. 5.

The “Catla” (C. buchanani), one of the largest Carps of the Ganges, growing to a length of more than three feet, and esteemed as food.

Labeo.—Scales of moderate or small size. Dorsal fin without osseous ray, with more than nine branched rays, commencing somewhat in advance of the ventrals. Snout obtusely rounded, the skin of the maxillary region being more or less thickened, forming a projection beyond the mouth. Mouth transverse, inferior, with the lips thickened, each or one of them being provided with an inner transverse fold, which is covered with a deciduous horny substance forming a sharp edge, which, however, does not rest upon the bone as base, but is soft and movable. Barbels very small, two or four; the maxillary barbels more or less hidden in a groove behind the angle of the mouth. Anal scales not enlarged. Pharyngeal teeth uncinate, 5. 4. 2.-2. 4. 5. Snout generally more or less covered with hollow tubercles.

About thirteen species are known from rivers of tropical Africa and the East Indies.

Discognathus.—Scales of moderate size. Dorsal fin without osseous ray, with not more than nine branched rays, commencing somewhat in advance of the ventrals. Snout obtusely rounded, more or less depressed, projecting beyond the mouth, more or less tubercular. Mouth inferior, transverse, crescent-shaped; lips broad, continuous, with an inner sharp edge of the jaws, covered with horny substance on the lower jaw; upper lip more or less distinctly fringed; lower lip modified into a suctorial disk, with free anterior and posterior margins. Barbels two or four; if two, the upper are absent. Anal scales not enlarged. Pectoral fins horizontal. Pharyngeal teeth, 5. 4. 2.-2. 4. 5.

A small fish (D. lamta), extremely abundant in almost all the mountain streams from Abyssinia and Syria to Assam.

Capoëta.—Scales small, of moderate or large size. Dorsal fin with or without a strong osseous ray, with not more than nine branched rays. Snout rounded, with the mouth transverse and at its lower side; each mandible angularly bent inwards in front, the anterior mandibular edge being nearly straight, sharpish, and covered with a horny brown layer. No lower labial fold. Barbels two (rarely four), or entirely absent. Anal scales not conspicuously enlarged. Pharyngeal teeth compressed, truncated, 5 or 4. 3. 2–2. 3. 4 or 5.

Characteristic of the fauna of Western Asia; one species from Abyssinia. Of the fifteen species known C. damascina deserves to be specially mentioned, being abundant in the Jordan and other rivers of Syria and Asia Minor.

Barbus.—Scales of small, moderate, or large size. Dorsal fin generally with the (third) longest simple ray ossified, enlarged, and frequently serrated; never, or only exceptionally, with more than nine branched rays, commencing opposite or nearly opposite to the root of the ventral fin. Eyes without adipose eyelid. Anal fin frequently very high. Mouth arched, without inner folds, inferior or anterior; lips without horny covering. Barbels short, four, two, or none. Anal scales not enlarged. Pharyngeal teeth 5. 4 or 3. 3 or 2.-2 or 3. 3 or 4. 5. Snout but rarely with tubercles or pore-like grooves.

No other genus of Cyprinoids is composed of so many species as the genus of “Barbels,” about 200 being known from the tropical and temperate parts of the Old World; it is not represented in the New World. Although the species differ much from each other in the form of the body, number of barbels, size of the scales, strength of the first dorsal ray or spine, etc., the transition between the extreme forms is so perfect that no further generic subdivision should be attempted. Some attain a length of six feet, whilst others never exceed a length of two inches. The most noteworthy are the large Barbels of the Tigris (B. subquincunciatus, B. esocinus, B. scheich, B. sharpeyi); the common Barbel of Central Europe and Great Britain (B. vulgaris); the “Bynni” of the Nile (B. bynni); B. canis from the Jordan; the “Mahaseer” of the mountain streams of India (B. mosal), probably the largest of all species, the scales of which are sometimes as large as the palm of a hand. The small, large-scaled species are especially numerous in the East Indies and the fresh waters of Tropical Africa.

Thynnichthys.—Scales small. Dorsal fin without an osseous ray, with not more than nine branched rays, commencing nearly opposite the ventrals. Head large, strongly compressed; eye without well-developed adipose membrane, in the middle of the depth of the head. Snout with the integuments very thin; there is no upper lip, and the lower jaw has a thin labial fold on the sides only. Mouth anterior and lateral; barbels none. Gill-rakers none; laminæ branchiales long, half as long as the post-orbital portion of the head; pseudobranchiæ none. Pharyngeal teeth lamelliform, with flat oblong crown, 5. 3 or 4. 2–2. 4 or 3. 5, the teeth of the three series being wedged into one another.

Three species from the East Indies.

Oreinus.—Scales very small. Dorsal fin with a strong osseous serrated ray, opposite to the ventrals. Snout rounded, with the mouth transverse, and at its lower side; mandibles broad, short, and flat, loosely joined together; margin of the jaw covered with a thick horny layer; a broad fringe-like lower lip, with free posterior margin. Barbels four. Vent and anal fin in a sheath, covered with enlarged tiled scales. Pharyngeal teeth pointed, more or less hooked, 5. 3. 2–2. 3. 5.

Three species from mountain streams of the Himalayas.

Schizothorax.—Hill-barbels, with the same singular sheath on each side of the vent, as in the preceding genus; but they differ in having the mouth normally formed, with mandibles of the usual length and width.

Seventeen species are known from fresh waters of the Himalayas, and north of them. Other genera from the same region, and with the anal sheath, are Ptychobarbus, Gymnocypris, Schizopygopsis, and Diptychus.

Gobio.—Scales of moderate size; lateral line present. Dorsal fin short, without spine. Mouth inferior; mandible not projecting beyond the upper jaw when the mouth is open; both jaws with simple lips; a small but very distinct barbel at the angle of the mouth, quite at the extremity of the maxillary. Gill-rakers very short; pseudobranchiæ. Pharyngeal teeth, 5. 3 or 2.—2 or 3. 5, hooked at the end.

The “Gudgeons” are small fishes of clear fresh waters of Europe; they are, like the barbels, animal feeders. In Eastern Asia they are represented by two closely allied genera, Ladislavia and Pseudogobio.

Ceratichthys.—Scales of moderate or small size; lateral line present. Dorsal fin short, without spine, not or but slightly in advance of the ventrals. Mouth subinferior; the lower jaw does not project beyond the upper when the mouth is open; intermaxillaries protractile from below the maxillaries; both jaws with thickish lips; a small barbel at the angle of the mouth, quite at the extremity of the maxillary. Gill-rakers very short and few in number: pseudobranchiæ. Pharyngeal teeth 4–4. hooked at the end (sometimes 4, 1—1. 4).

About ten species are known from North America; they are small, and called “Chub” in the United States. C. biguttatus is, perhaps, the most widely-diffused Freshwater-fish in the United States, and common everywhere. Breeding males have generally a red spot on each side of the head.

Other similar genera from the fresh waters of North America, and generally called “Minnows,” are Pimephales (the “Black Head”), Hyborhynchus, Hybognathus, Campostoma (the “Stone-lugger”), Ericymba, Cochlognathus, Exoglossum (the “Stone Toter” or “Cut-lips”), and Rhinichthys (the “Long-nosed Dace”).

The remaining Old World genera belonging to the group Cyprinina are Cirrhina, Dangila, Osteochilus, Barynotus, Tylognathus, Abrostomus, Crossochilus, Epalzeorhynchus, Barbichthys, Amblyrhynchichthys, Albulichthys, Aulopyge, Bungia, and Pseudorasbora.

III. Rohteichthyina.—Anal fin very short, with not more than six branched rays. Dorsal fin behind ventrals. Abdomen compressed. Lateral line running along the median line of the tail. Mouth without barbels. Pharyngeal teeth in a triple series.

One genus and species only, Rohteichthys microlepis, from Borneo and Sumatra.

IV. Leptobarbina.—Anal fin very short, with not more than six branched rays. Dorsal fin opposite to ventrals. Abdomen not compressed. Lateral line running in the lower half of the tail. Barbels present, not more than four in number. Pharyngeal teeth in a triple series.

One genus and species only, Leptobarbus hoevenii, from Borneo and Sumatra.

V. Rasborina.—Anal fin very short, with not more than six branched rays. Dorsal fin inserted behind the origin of the ventrals. Abdomen not compressed. Lateral line running along the lower half of the tail, if complete. Mouth sometimes with barbels, which are nevermore than four in number. Pharyngeal teeth in a triple, or single series. Air-bladder present, without osseous covering.

Rasbora.—Scales large, or of moderate size, there being generally four and a half longitudinal series of scales between the origin of the dorsal fin and the lateral line, and one between the lateral line and the ventral. Lateral line curved downwards. Dorsal fin with seven or eight branched rays, not extending to above the anal, which is seven-rayed. Mouth of moderate width, extending to the front margin of the orbit, with the lower jaw slightly prominent, and provided with three prominences in front, fitting into grooves of the upper jaw; barbels none, in one species two. Gill-rakers short, lanceolate. Pseudobranchiæ. Pharyngeal teeth in three series, uncinate.

Thirteen species of small size from the East Indian Continent and Archipelago, and from rivers on the east coast of Africa.

Amblypharyngodon.—Scales small; lateral line incomplete. Dorsal fin without an osseous ray, with not more than nine branched rays, commencing a little behind the origin of the ventrals. Head of moderate size, strongly compressed; eye without adipose membrane; snout with the integuments very thin; there is no upper lip, and the lower jaw has a short labial fold on the sides only. Mouth anterior, somewhat directed upwards, with the lower jaw prominent. Barbels none. Gill-rakers extremely short; pseudobranchiæ. Pharyngeal teeth molar-like, with their crowns concave, 3. 2. 1.—1. 2. 3. Intestinal tract narrow, with numerous convolutions.

Three species of small size from the Continent of India.

To the same group belong Luciosoma, Nuria, and Aphyocypris, from the same geographical region.

VI. Semiplotina.—Anal fin short, with seven branched rays, not extending forwards to below the dorsal. Dorsal fin elongate, with an osseous ray. Lateral line running along the middle of the tail. Mouth sometimes with barbels.

Two genera: Cyprinion, from Syria and Persia, and Semiplotus from Assam.

VII. Xenocypridina.—Anal fin rather short, with seven or more branched rays, not extending forwards to below the dorsal fin. Dorsal short, with an osseous ray. Lateral line running along the middle of the tail. Mouth sometimes with barbels. Pharyngeal teeth in a triple or double series.

Three genera: Xenocypris and Paracanthobrama from China; and Mystacoleucus from Sumatra.

VIII. Leuciscina.—Anal fin short or of moderate length, with from eight to eleven branched rays, not extending forwards to below the dorsal. Dorsal fin short, without osseous ray. Lateral line, if complete, running along, or nearly in, the middle of the tail. Mouth generally without barbels. Pharyngeal teeth in a single or double series.

Leuciscus.—Body covered with imbricate scales. Dorsal fin commencing opposite, rarely behind, the ventrals. Anal fin generally with from nine to eleven, rarely with eight (in small species only), and still more rarely with fourteen rays. Mouth without structural peculiarities; lower jaw not trenchant; barbels none. Pseudobranchiæ. Pharyngeal teeth conical or compressed, in a single or double series. Intestinal tract short, with only a few convolutions.

The numerous species of this genus are comprised under the name of “White-fish;” they are equally abundant in the northern temperate zone of both hemispheres, about forty species being known from the Old World, and about fifty from the New. The most noteworthy species of the former Fauna are the “Roach” (L. rutilus, see Fig. [21], p. 50), common all over Europe north of the Alps; the “Chub” (L. cephalus), extending into Northern Italy and Asia Minor; the “Dace” (L. leuciscus), a companion of the Roach; the “Id” or “Nerfling” (L. idus), from the central and northern parts of Continental Europe, domesticated in some localities of Germany, in this condition assuming the golden hue of semi-albinism, like a Gold-fish, and then called the “Orfe;” the “Rudd,” or “Red-eye” (L. erythrophthalmus), distributed all over Europe and Asia Minor, and distinguished by its scarlet lower fins; the “Minnow” (L. phoxinus), abundant everywhere in Europe, and growing to a length of seven inches in favourable localities. The North American species are much less perfectly known; the smaller ones are termed “Minnows,” the larger “Shiner” or “Dace.” The most common are L. cornutus (Red-fin, Red Dace); L. neogæus, a minnow resembling the European species, but with incomplete lateral line; L. hudsonius, the “Spawn-eater” or “Smelt.”

Tinca.—Scales small, deeply embedded in the thick skin; lateral line complete. Dorsal fin short, its origin being opposite the ventral fin; anal short; caudal subtruncated. Mouth anterior; jaws with the lips moderately developed; a barbel at the angle of the mouth. Gill-rakers short, lanceolate; pseudobranchiæ rudimentary. Pharyngeal teeth 4 or 5.-5, cuneiform, slightly hooked at the end.

Fig. 274.—The Tench (Tinca tinca).

Only one species of “Tench” is known (T. tinca), found all over Europe in stagnant waters with soft bottom. The “Golden Tench” is only a variety of colour, an incipient albinism like the Gold-fish and Id. Like most other Carps of this group it passes the winter in a state of torpidity, during which it ceases to feed. It is extremely prolific, 297,000 ova having been counted in one female; its spawn is of a greenish colour.

Leucosomus.—Scales of moderate or small size; lateral line present. Dorsal fin commencing opposite, or nearly opposite, to the ventral. Anal fin short. Mouth anterior or sub-anterior; intermaxillaries protractile. A very small barbel at the extremity of the maxillary. Lower jaw with rounded margin, and with the labial folds well developed laterally. Gill-rakers short; pseudobranchiæ. Pharyngeal teeth in a double series.

A North American genus, to which belong some of the most common species of the United States. L. pulchellus (the “Fall-fish,” “Dace,” or “Roach”), one of the largest White-fishes of the Eastern States, attaining to a length of 18 inches, and abundant in the rapids of the larger rivers. L. corporalis (the “Chub”), common everywhere from New England to the Missouri region.

Chondrostoma.—Scales of moderate size or small. Lateral line terminating in the median line of the depth of the tail. Dorsal fin with not more than nine branched rays, inserted above the root of the ventrals. Anal fin rather elongate, with ten or more rays. Mouth inferior, transverse, lower jaw with a cutting edge, covered with a brown horny layer. Barbels none. Gill-rakers short, fine; pseudobranchiæ. Pharyngeal teeth 5 or 6 or 7.-7 or 6 or 5, knife-shaped, not denticulated. Peritoneum black.

Seven species from the Continent of Europe and Western Asia.

Other Old World genera belonging to the Leuciscina are Myloleucus, Ctenopharyngodon, and Paraphoxinus; from North America: Mylopharodon, Meda, Orthodon, and Acrochilus.

IX. Rhodeina.—Anal fin of moderate length, with from nine to twelve branched rays, extending forwards to below the dorsal. Dorsal fin short, or of moderate length. Lateral line, if complete, running along or nearly in the middle of the tail. Mouth with very small, or without any barbels. Pharyngeal teeth in a single series.

Very small roach-like fishes inhabiting chiefly Eastern Asia and Japan, one species (Rh. amarus) advancing into Central Europe. The thirteen species known have been distributed among four genera, Achilognathus, Acanthorhodeus, Rhodeus, and Pseudoperilampus. In the females a long external urogenital tube is developed annually during the spawning season. The European species is known in Germany by the name of “Bitterling.”

X. Danionina.—Anal fin of moderate length or elongate, with not less, and generally more, than eight branched rays. Lateral line running along the lower half of the tail. Mouth with small, or without any, barbels. Abdomen not trenchant. Pharyngeal teeth in a triple or double series.

Small fishes from the East Indian Continent, Ceylon, the East Asiatic Islands, and a few from East African Rivers, The genera belonging to this group are Danio, Pteropsarion, Aspidoparia, Barilius, Bola, Scharca, Opsariichthys, Squaliobarbus, and Ochetobus: altogether about forty species.

XI. Hypophthalmichthyina.—Anal fin elongate. Lateral line running nearly along the median line of the tail. Mouth without barbels. Abdomen not trenchant. No dorsal spine. Pharyngeal teeth in a single series.

One genus (Hypophthalmichthys) with two species from China.

XII. Abramidina.—Anal fin elongate. Abdomen, or part of the abdomen, compressed.

Fig. 275.—The Bream ( Abramis brama).

Abramis.—Body much compressed, elevated, or oblong. Scales of moderate size. Lateral line present, running in the lower half of the tail. Dorsal fin short, with spine, opposite to the space between ventrals and anals. Lower jaw generally shorter, and rarely longer than the upper. Both jaws with simple lips, the lower labial fold being interrupted at the symphysis of the mandible. Upper jaw protractile. Gill-rakers rather short; pseudobranchiæ. The attachment of the branchial membrane to the isthmus takes place at some distance behind the vertical from the orbit. Pharyngeal teeth in one or two series, with a notch near the extremity. Belly behind the ventrals compressed into an edge, the scales not extending across it.

The “Breams” are represented in the temperate parts of both northern hemispheres; in Europe there occur the “Common Bream,” A. brama; the “Zope,” A. ballerus; A. sapa; the “Zärthe,” A. vimba; A. elongatus; the “White Bream,” A. blicca; A. bipunctatus. Of these A. brama and A. blicca are British; the former being one of the most common fishes, and sometimes attaining to a length of two feet. Crosses between these two species, and even with other Cyprinoids, are not rare. Of the American species A. americanus (“Shiner,” “Bream”) is common and widely distributed; like the European Bream it lives chiefly in stagnant waters or streams with a slow current.

Aspius.—Body oblong; scales of moderate size; lateral line complete, terminating nearly in the middle of the depth of the tail. Dorsal fin short, without spine, opposite to the space between the ventrals and anal; anal fin elongate, with thirteen or more rays. Lower jaw more or less conspicuously projecting beyond the upper. Lips thin, simple, the lower labial fold being at the symphysis; upper jaw but little protractile. Gill-rakers short and widely set; pseudobranchiæ. The attachment of the branchial membrane to the isthmus takes place below the hind margin of the orbit. Pharyngeal teeth hooked, 5. 3.-3 or 2. 5 or 4. Belly behind the ventrals compressed, the scales covering the edge.

Four species from Eastern Europe to China.

Alburnus.—Body more or less elongate; scales of moderate size; lateral line present, running below the median line of the tail. Dorsal fin short, without spine, opposite to the space between ventrals and anal; anal fin elongate, with more than thirteen rays. Lower jaw more or less conspicuously projecting beyond the upper. Lips thin, simple, the lower labial fold being interrupted at the symphysis of the mandible. Upper jaw protractile. Gill-rakers slender, lanceolate, closely set; pseudobranchiæ. The attachment of the branchial membrane to the isthmus takes place below the hind margin of the orbit. Pharyngeal teeth in two series, hooked. Belly behind the ventrals compressed into an edge, the scales not extending across it.

“Bleak” are numerous in Europe and Western Asia, fifteen species being known. The common Bleak (A. alburnus) is found north of the Alps only, and represented by another species (A. alburnellus, “Alborella,” or “Avola”) in Italy.

Of the other genera referred to this group, Leucaspius and Pelecus belong to the European Fauna; Pelotrophus is East African; all the others occur in the East Indies or the temperate parts of Asia, viz. Rasborichthys, Elopichthys, Acanthobrama (Western Asia), Osteobrama, Chanodichthys, Hemiculter, Smiliogaster, Toxabramis, Culter, Eustira, Chela, Pseudolabuca, and Cachius.

XIII. Homalopterina.—Dorsal and anal fins short, the former opposite to ventrals. Pectoral and ventral fins horizontal, the former with the outer rays simple. Barbels six or none. Air-bladder absent. Pharyngeal teeth in a single series, from ten to sixteen in number.

Inhabitants of hill-streams in the East Indies; they are of small size and abundant where they occur. Thirteen species are known belonging to the genera Homaloptera, Gastromyzon, Crossostoma, and Psilorhynchus.

XIV. Cobitidina.—Mouth surrounded by six or more barbels. Dorsal fin short or of moderate length; anal fin short. Scales small, rudimentary, or entirely absent. Pharyngeal teeth in a single series, in moderate number. Air-bladder partly or entirely enclosed in a bony capsule. Pseudobranchiæ none: Loaches.

Misgurnus.—Body elongate, compressed. No sub-orbital spine. Ten or twelve barbels, four belonging to the mandible. Dorsal fin opposite to the ventrals; caudal rounded.

Four species from Europe and Asia. M. fossilis is the largest of European Loaches, growing to a length of ten inches; it occurs in stagnant waters of eastern and southern Germany and northern Asia. In China and Japan it is replaced by an equally large species, M. anguillicaudatus.

Nemachilus.—No erectile sub-orbital spine. Six barbels, none at the mandible. Dorsal fin opposite to the ventrals.

The greater number of Loaches belong to this genus; about fifty species are known from Europe and temperate Asia; such species as extend into tropical parts inhabit streams of high altitudes. Loaches are partial to fast-running streams with stony bottom, and exclusively animal feeders. In spite of their small size they are esteemed as food where they occur in sufficient abundance. The British species, N. barbatulus, is found all over Europe except Denmark and Scandinavia.

Cobitis.—Body more or less compressed, elongate; back not arched. A small, erectile, bifid sub-orbital spine below the eye. Six barbels only on the upper jaw. Dorsal fin inserted opposite to ventrals. Caudal rounded or truncate.

Only three species are known, of which C. tænia occurs in Europe. It is scarce and very local in Great Britain.

Botia.—Body compressed, oblong; back more or less arched. Eyes with a free circular eyelid; an erectile bifid sub-orbital spine. Six barbels on the upper jaw, sometimes two others at the mandibulary symphysis. Dorsal fin commencing in advance of the root of the ventrals; caudal fin forked. Air-bladder consisting of two divisions: the anterior enclosed in a partly osseous capsule, the posterior free, floating in the abdominal cavity.

Fig. 276.—Botia rostrata. From Bengal.

This genus is more tropical than any of the preceding, and the majority of the species (eight in number) are finely coloured. The more elevated form of their body, and the imperfect ossification of the capsules of the air-bladder, the divisions of which are not side by side, but placed in the longitudinal axis of the body, indicate likewise that this genus is more adapted for still waters of the plains than for the currents of hill-streams.

Other genera from tropical India are Lepidocephalichthys, Acanthopsis, Oreonectes (hills near Hong-Kong), Paramisgurnus (Yan-tse-Kiang), Lepidocephalus, Acanthophthalmus, and Apua.

Fourth Family—Kneriidæ.

Body scaly, head naked. Margin of the upper jaw formed by the intermaxillaries. Dorsal and anal fins short, the former belonging to the abdominal portion of the vertebral column. Teeth none, either in the mouth or pharynx. Barbels none. Stomach siphonal; no pyloric appendages. Pseudobranchiæ none. Branchiostegals three; air-bladder long, not divided. Ovaries closed.

Small loach-like fishes from fresh waters of tropical Africa; two species only, Kneria angolensis and K. spekii, are known.

Fifth Family—Characinidæ.

Body covered with scales, head naked; barbels none. Margin of the upper jaw formed by the intermaxillaries in the middle and by the maxillaries laterally. Generally a small adipose fin behind the dorsal. Pyloric appendages more or less numerous; air-bladder transversely divided into two portions, and communicating with the organ of hearing by means of the auditory ossicles. Pseudobranchiæ none.

The fishes of this family are confined to the fresh waters of Africa, and especially of tropical America, where they replace the Cyprinoids, with which family, however, they have but little in common as far as their structural characteristics are concerned. Their co-existence in Africa with Cyprinoids proves only that that continent is nearer to the original centre, from which the distribution of Cyprinoids commenced than tropical America. The family includes herbivorous as well as strictly carnivorous forms; some are toothless, whilst others possess a most formidable dentition. The family contains so many diversified forms as to render a subdivision into groups necessary. They have not yet been obtained in fossiliferous strata.

I. Erythrinina.—Adipose fin absent.

The sixteen species of this group belong to the fauna of tropical America, and are referred to the genera Macrodon, Erythrinus, Lebiasina, Nannostomus, Pyrrhulina, and Corynopoma.

II. Curimatina.—A short dorsal and an adipose fin; dentition imperfect. Tropical America.

Curimatus.—Dorsal fin placed nearly in the middle of the body; anal rather short or of moderate length; ventrals below the dorsal. Body oblong or elevated, with the belly rounded or flattened before the ventrals. Cleft of the mouth transverse, lips none, margins of the jaws trenchant. No teeth whatever. Intestinal tract very long and narrow.

About twenty species are known, of rather small size.

The other genera of this group have teeth, but they are either rudimentary or absent in some part of the jaws: Prochilodus, Cænotropus, Hemiodus, Saccodon, Parodon.

III. Citharinina.—A rather long dorsal and an adipose fin; minute labial teeth. Tropical Africa.

One genus only, Citharinus, with two species, is known. Common in the Nile, attaining to a length of three feet.

IV. Anastomatina.—A short dorsal and an adipose fin; teeth in both jaws well developed; the gill-membranes grown to the isthmus; nasal openings remote from each other. Tropical America.

Leporinus.—Dorsal fin placed nearly in the middle of the length of the body; anal short; ventrals below the dorsal. Body oblong, covered with scales of moderate size; belly rounded. Cleft of the mouth small, with the lips well developed; teeth in the intermaxillary and mandible, few in number, flattened, with the apex more or less truncated, and not serrated; the middle pair of teeth is the longest in both jaws; palate toothless.

This genus is generally distributed in the rivers east of the Andes; about twenty species are known, some of which, like L. frederici, L. megalepis, are very common. They are well marked by black bands or spots, and rarely grow to a length of two feet, being generally much smaller.—The other genera belonging to this group are Anastomus and Rhytiodus.

V. Nannocharacina.—A short dorsal and an adipose fin; teeth in both jaws well developed; notched incisors. The gill-membranes are grown to the isthmus. Nostrils close together.

One genus, Nannocharax, with two species only, from the Nile and Gaboon; very small.

VI. Tetragonopterina.—A short dorsal and an adipose fin; the teeth in both jaws well developed, compressed, notched, or denticulated; the gill-membranes free from the isthmus, and the nasal openings close together. South America and Tropical Africa.

Alestes.—The dorsal fin is placed in the middle of the length of the body, above or behind the ventrals; anal fin rather long. Body oblong, covered with scales of moderate or large size; belly rounded. Cleft of the mouth rather small. Maxillary teeth none; intermaxillary teeth in two series; those of the front series more or less compressed, more or less distinctly tricuspid; the teeth of the hinder series are broad, molar-like, each armed with several pointed tubercles. Teeth in the lower jaw in two series; those in the front series laterally compressed, broader behind than in front; the hinder series is composed of two conical teeth. All the teeth are strong, few in number.

Fourteen species from Tropical Africa; several inhabit the Nile, of which the “Raches” (A. dentex and A. kotschyi) are the most common.

Tetragonopterus.—The dorsal fin is placed in the middle of the length of the body, above or immediately behind the ventrals; anal fin long. Body oblong or elevated, covered with scales of moderate size; belly rounded. Cleft of the mouth of moderate width. Anterior teeth strong, lateral teeth small. Intermaxillary and mandibulary teeth subequal in size, with a compressed and notched crown, the former in a double, the latter in a single series; maxillary with a few teeth near its articulation, rarely with the entire edge denticulated.

Of all the genera of this family Tetragonopterus is represented by the greatest number of species; about fifty are known. Some of them seem to have a very wide range, whilst others are merely local. All are of small size, rarely exceeding a length of eight inches.

Chirodon.—Dorsal fin placed in the middle of the length of the body, behind the ventrals; anal long or of moderate length. Body oblong, covered with scales of moderate size; lateral line not continued to the tail. Belly rounded before the ventrals. Cleft of the mouth narrow, maxillary short. A single series of small serrated teeth in the intermaxillary and mandibulary; maxillary teeth none.

Fig. 277.—Chirodon alburnus.

Three species of small size from various parts of South America; the species figured is represented of the natural size, and comes from the Upper Amazons.

Megalobrycon.—Dorsal fin placed in middle of the length of the body, immediately behind the ventrals. Anal long. Abdomen rounded in front of, and somewhat compressed behind, the ventrals. Cleft of the mouth of moderate width. Teeth notched, in a triple series in the intermaxillary, and in a single in the maxillary and mandible; no other teeth behind the mandibulary teeth or on the palate. Scales of moderate size, with the free portion striated.

One species from the Upper Amazons (M. cephalus). Specimens more than one foot long have been obtained.

Fig. 278.—Megalobrycon cephalus.

Gastropelecus.—Dorsal fin placed behind the middle of the length of the body, above the anal; anal long; pectoral long; ventrals very small or rudimentary. Body strongly compressed, with the thoracic region dilated into a sub-semicircular disk. Scales of moderate size. Lateral line descending obliquely backwards towards the origin of the anal fin. The lower profile compressed into an acute ridge. Cleft of the mouth of moderate width; teeth compressed, tricuspid, in one or two series in the intermaxillary, and in a single in the mandible; maxillary with a few minute conical teeth; palate toothless.

Three specimens of this singular form are known from Brazil and the Guyanas; they are of very small size.

The majority of the other genera belonging to this group are South American, viz. Piabucina, Scissor, Pseudochalceus, Aphyocharax, Chalceus, Brycon, Chalcinopsis, Bryconops, Creagrutus, Chalcinus, Piabuca, Paragoniates, and Agoniates; two only are African, viz. Nannæthiops, which represents the South American Tetragonopterus, and Bryconæthiops, which is allied to Brycon.

VII. Hydrocyonina.—A short dorsal and an adipose fin; teeth in both jaws well developed and conical; gill membranes free from the isthmus; nasal openings close together. South America and Tropical Africa. Fishes of prey.

Hydrocyon.—The dorsal fin is in the middle of the length of the body, above the ventrals; anal of moderate length. Body oblong, compressed, covered with scales of moderate size; belly rounded. Cleft of the mouth wide, without lips; the intermaxillaries and mandibles are armed with strong pointed teeth, widely set and few in number; they are received in notches of the opposite jaw, and visible externally when the mouth is closed. Palate toothless. Cheeks covered with the enlarged sub-orbital bones. Orbit with an anterior and posterior adipose eyelid. Intestinal tract short.

Four species from Tropical Africa; two occur in the Nile, H. forskalii being abundant, and well known by the names “Kelb el bahr” and “Kelb el moyeh.” Their formidable dentition renders them most destructive to other fishes; they grow to a length of four feet.

Cynodon.—Dorsal fin placed behind, or nearly in, the middle of the length of the body, behind the ventrals; anal long. Head and body compressed, oblong, the latter covered with very small scales; belly compressed, keeled. Teeth in the intermaxillary, maxillary, and mandible in a single series, conical, widely set, of unequal size; a pair of very large canine teeth anteriorly in the lower jaw, received in two grooves on the palate; palate with patches of minute granulated teeth. The outer branchial arch without gill-rakers, but with very short tubercles.

Four species from Brazil and the Guyanas; they are as formidable fishes of prey as the preceding, and grow to the same size.

With the exception of Sarcodaces, all the remaining genera of this group belong to the fauna of Tropical America, viz. Anacyrtus, Hystricodon, Salminus, Oligosarcus, Xiphorhamphus, and Xiphostoma.

VIII. Distichodontina.—Dorsal fin rather elongate; adipose fin present. Gill-membranes attached to the isthmus; belly rounded. Tropical Africa.

The species, ten in number, belong to one genus only (Distichodus), well known on the Nile under the name of “Nefasch.” They grow to a considerable size, being sometimes four feet long and one and a half foot deep. They are used as food.

IX. Ichthyborina.—An adipose fin; number of dorsal rays increased (12–17); gill-membranes free from the isthmus. Belly rounded; canine teeth. Tropical Africa.

Two genera only: Ichthyborus from the Nile, and Phago from West Africa. Small fishes of very rare occurrence.

X. Crenuchina.—Dorsal fin rather elongate; an adipose fin. Gill-membranes free from the isthmus, with the belly rounded, and without canine teeth.

This small group is represented in the Essequibo by a single species, Crenuchus spilurus, and by another in West Africa, Xenocharax spilurus.

XI. Serrasalmonina.—Dorsal fin rather elongate; an adipose fin. Gill-membranes free from the isthmus; belly serrated. Tropical America.

Although the fishes of this family do not attain any considerable size, the largest scarcely exceeding two feet in length, their voracity, fearlessness, and number renders them a perfect pest in many rivers of tropical America. In all, the teeth are strong, short, sharp, sometimes lobed incisors, arranged in one or more series; by means of them they cut off a mouthful of flesh as with a pair of scissors; and any animal falling into the water where these fishes abound is immediately attacked and cut in pieces in an incredibly short time. They assail persons entering the water, inflicting dangerous wounds before the victims are able to make their escape. In some localities it is scarcely possible to catch fishes with the hook and line, as the fish hooked is immediately attacked by the “Caribe” (as these fishes are called), and torn to pieces before it can be withdrawn from the water. The Caribes themselves are rarely hooked, as they snap the hook or cut the line. The smell of blood is said to attract at once thousands of these fishes to a spot. They are most abundant in the Brazils and Guyanas; some forty species are known, and referred to the genera Mylesinus, Serrasalmo, Myletes, and Catoprion.

Fig. 279.—Serrasalmo scapularis, from the Essequibo.

Sixth Family—Cyprinodontidæ.

Head and body covered with scales; barbels none. Margin of the upper jaw formed by the intermaxillaries only. Teeth in both jaws; upper and lower pharyngeals with cardiform teeth. Adipose fin none; dorsal fin situated on the hinder half of the body. Stomach without blind sac; pyloric appendages none. Pseudobranchiæ none; air-bladder simple, without ossicula auditus.

Small fishes, inhabiting fresh, brackish, and salt water of Southern Europe, Africa, Asia, and America. The majority are viviparous; and to facilitate copulation the anal fin of the adult male of many species is modified into a copulatory organ, which is probably (partially at least) introduced into the vulva of the female; but it is uncertain whether it serves to conduct the semen, or merely to give the male a firmer hold of the female during the act. Also secondary sexual differences are developed in the Cyprinodonts; the males are always the smaller, sometimes several times smaller than the females, quite diminutive; and they are perhaps the smallest fishes in existence. The fins generally are more developed in the males, and the coloration is frequently different also. Some species are carnivorous; others live on the organic substances mixed with mud. Fossil remains have been found in tertiary strata, all apparently referable to the existing genus Cyprinodon; they occur near Aix in Provence, in the marl of Gesso, St. Angelo, in the Brown coal near Bonn, near Frankfort, and in the freshwater-chalk of Oeningen. In the latter locality a Poecilia occurs likewise.

The genera can be divided into two groups:

I. Cyprinodontidæ Carnivoræ.—The bones of each ramus of the mandible are firmly united; intestinal tract short, or but little convoluted. Carnivorous or insectivorous.

Cyprinodon.—Cleft of the mouth small, developed laterally and horizontally. Snout short. Teeth of moderate size, incisor-like, notched, in a single series. Scales rather large. Origin of the anal fin behind that of the dorsal in both sexes, both fins being larger in the male than in the female. Anal not modified into a sexual organ.

Seven species occur in the Mediterranean region, all of which seem able to live in briny springs or pools, the water of which contains a much greater percentage of salts than sea-water, as the brine-springs near the Dead Sea or in the Sahara. They are as little affected by the high temperature of some of these springs (91°), for instance of that at Sidi Ohkbar in the Sahara. Like other fishes living in limited localities or concealing themselves in mud, Cyprinodonts lose sometimes their ventral fins; such specimens have been described as Tellia. The species of the New World are less known than those of the Old, but not less numerous.

Allied to Cyprinodon are Fitzroyia from Monte Video, and Characodon from Central America.

Haplochilus.—Snout flat, both jaws being much depressed, and armed with a narrow band of villiform teeth. Body oblong, depressed anteriorly, compressed posteriorly. Dorsal fin short, commencing behind the origin of the anal, which is more or less elongate.

Twenty species from the East Indies, tropical Africa, and temperate and tropical America.

Fundulus.—Cleft of the mouth of moderate width, developed laterally and horizontally. Snout of moderate length. Teeth in a narrow band, those of the outer series being largest, conical. Scales of moderate size. Dorsal fin commencing before or opposite the origin of the anal. Sexes not differentiated.

“Killifish,” abundant in the New World, where about twenty species have been found; F. heteroclitus, majalis, diaphanus, being common on the Atlantic coast of the United States; from the Old World two species only are known, viz. F. hispanicus from Spain, and F. orthonotus from the east coast of Africa. Allied to Fundulus are the South American Limnurgus, Lucania, Rivulus, and Cynolebias.

Orestias.—Ventral fins none. Cleft of the mouth of moderate width, directed upwards, with the lower jaw prominent, and with the upper protractile. Both jaws with a narrow band Of small conical teeth. Scales rather small or of moderate size, those on the head and upper part of the trunk frequently enlarged, plate-like, and granulated. Dorsal and anal fins moderately developed, opposite to each other. Sexes not differentiated by modification of the anal fin. The gill-membranes of both sides are united for a short distance, and not attached to the isthmus.

Inhabitants of Lake Titicaca and other elevated sheets of water on the Cordilleras of Peru and Bolivia, between the 14th and 19th degrees of latitude, at an elevation of 13,000 and 14,000 feet above the level of the sea. Singularly, the fishes of this outlying genus attain to a greater size than any other members of this family, being about eight inches long and comparatively bulky. They are considered a delicacy. Six species.

Jenynsia.—Cleft of the mouth small, developed laterally and horizontally; snout not produced. Both jaws with a series of tricuspid teeth of moderate size. Scales of moderate size. The origin of the anal fin is, in both sexes, behind that of the dorsal, although the anal of the male is modified into an intromittent organ, in which scarcely any of the rays remain distinct.

One species from Maldonado.

Fig. 280.—Gambusia punctata, from Cuba. A. Male; B. Female.

Gambusia.—Cleft of the mouth developed laterally and horizontally. Snout not produced, with the lower jaw more or less prominent. Both jaws with a band of teeth, those of the outer series being strongest and conical. Scales rather large. Origin of the anal fin more or less in advance of that of the dorsal. Anal fin of the male modified into an intromittent organ and much advanced.

Eight species from the West Indies and the southern parts of South America.—Allied genera are the Central American Pseudoxiphophorus and Belonesox.

Anableps.—Head broad and depressed, with the supraorbital part very much raised. Body elongate, depressed anteriorly and compressed posteriorly. Cleft of the mouth horizontal, of moderate width, the mandible being short; upper jaw protractile. Both jaws armed with a band of villiform teeth, those of the outer series being largest and somewhat movable. The integuments of the eye are divided into an upper and lower portion by a dark-coloured transverse band of the conjunctiva; also the pupil is completely divided into two by a pair of lobes projecting from each side of the iris. Scales rather small or of moderate size. Dorsal and anal fins short, the former behind the latter. The anal fin of the male is modified into a thick and long scaly conical organ with an orifice at its extremity.

Three species from tropical America. They are the longest Cyprinodonts, attaining to the length of nearly twelve inches. Their peculiar habit of swimming with part of the head out of the water has been noticed above (p. 113).

II. Cyprinodontidæ Limnophagæ.—The bones of each ramus of the mandible are but loosely joined; intestinal tract with numerous circumvolutions. Sexes differentiated. Mud-eating. Tropical America.

Poecilia.—Cleft of the mouth small, transverse; mandible very short. Both jaws with a narrow band of minute teeth. Scales rather large. Origin of the anal fin generally nearly opposite to that of the dorsal fin in the female, but in the male it is modified into an intromittent organ and much advanced. Dorsal fin short, with not more than eleven rays.

Sixteen species.

Mollienesia.—Differing from Poecilia in having a larger dorsal fin, with twelve or more rays.

Five species. The males are most beautifully coloured, and their dorsal fin is much enlarged. In one species (M. hellerii), besides, the lower caudal rays of the mature male are prolonged into a long, sword-shaped, generally black and yellow appendage.

Two other genera belong to this group: Platypoecilus and Girardinus.

Seventh Family—Heteropygii.

Head naked; body covered with very small scales; barbels none. Margin of the upper jaw formed, by the intermaxillaries. Villiform teeth in the jaws and on the palate. Adipose fin none. Dorsal fin belonging to the caudal portion of the vertebral column, opposite to the anal. Ventral fins rudimentary or absent. Vent situated before the pectorals. Stomach coecal; pyloric appendages present. Pseudobranchiæ none; air-bladder deeply notched anteriorly.

To this small family, which is closely allied to the Cyprinodonts and Umbridæ, belongs the famous Blind Fish of the Mammoth Cave in Kentucky, Amblyopsis spelæus. It is destitute of external eyes, and the body is colourless; although the eyes, with the optic nerve, are quite rudimentary, the optic lobes are as much developed as in fishes with perfect eyes. The loss of vision is compensated by the acuteness of its sense of hearing, as well as by a great number of tactile papillæ, arranged on transverse ridges on the head, and provided with nervous filaments coming from the fifth pair. The ovary is single, and the fish is viviparous, like the Cyprinodonts. It seems to occur in all the subterranean rivers that flow through the great limestone region underlying the carboniferous rocks in the central portion of the United States. As in Cyprinodon, so in this genus, specimens occur without ventral fins; they have been called Typhlichthys. The largest size to which Amblyopsis grows is five inches.

Chologaster is closely allied, but provided with small external eyes; its body is coloured, but it is destitute of ventrals. It was found once in a rice field in South Carolina.

[See Tellkampf, Müll. Arch. 1844, p. 381; Packard and Putnam, “The Mammoth Cave and its Inhabitants.” Salem. 1872. 8^o.]

Eighth Family—Umbridæ.

Head and body covered with scales; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Adipose fin none; the dorsal fin belongs partly to the abdominal portion of the vertebral column. Stomach siphonal; pyloric appendages none; pseudobranchiæ glandular, hidden; air-bladder simple.

Two small species only are known: Umbra krameri from Austria and Hungary, and Umbra limi, locally distributed in the United States; called “Hunds-fish” in Germany, “Dog-fish” or “Mud-fish” in America.

Ninth Family—Scombresocidæ.

Body covered with scales; a series of keeled scales along each side of the belly. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Lower pharyngeals united into a single bone. Dorsal fin opposite the anal, belonging to the caudal portion of the vertebral column. Adipose fin none. Air-bladder generally present, simple, sometimes cellular, without pneumatic duct. Pseudobranchiæ hidden, glandular. Stomach not distinct from the intestine, which is quite straight, without appendages.

The fishes of this family are chiefly marine, some living in the open ocean, whilst others have become acclimatised in fresh water; many of the latter are viviparous, all the marine forms being oviparous. They are found in all the temperate and tropical zones. Carnivorous.

This family is represented in the strata of Monte Bolca by rare remains of a fish named Holosteus, allied to Belone or Scombresox, and by a species of Belone in the miocene of Licata.

Belone.—Both jaws are prolonged into a long slender beak. All the dorsal and anal rays connected by membrane.

The long upper jaw of the “Gar-pike” is formed by the intermaxillaries, which are united by a longitudinal suture. Both jaws are beset with asperities, and with a series of longer, conical-pointed, widely-set teeth. Skimming along the surface of the water, the Gar-pike seize with these long jaws small fish as a bird would seize them with its beak; but their gullet is narrow, so that they can swallow small fish only. They swim with an undulating motion of the body; although they are in constant activity, their progress through the water is much slower than that of the Mackerels, the shoals of which sometimes appear simultaneously with them on our coasts. Young specimens are frequently met in the open ocean; when very young their jaws are not prolonged, and during growth the lower jaw is much in advance of the upper, so that these young fishes resemble a Hemirhamphus. About fifty species are known from tropical and temperate seas, Belone belone being a common fish on the British coast. Its bones, like those of all its congeners, are green; and therefore the fish, although good eating, is disliked by many persons. Some species attain a length of five feet.

Scombresox.—Both jaws are prolonged into a long slender beak. A number of detached finlets behind the dorsal and anal fins.

The “Saury” or “Skipper” resemble the Gar-pike, but the teeth in the jaws are minute; they seem to feed chiefly on soft pelagic animals. In their habits they are still more pelagic; and the young, in which the beak is still undeveloped, are met with everywhere in the open ocean, in the Atlantic as well as in the Pacific. The European species, Sc. saurus, is not rare on the British coast; four other species have been described, closely allied to Sc. saurus.

Hemirhamphus.—The lower jaw only is prolonged into a long slender beak.

In the young both jaws are short; the upper is never prolonged, the intermaxillaries forming a triangular, more or less convex, plate. The “Half-beaks” are common between and near the tropics; some forty species are known, none of which attain to the same length as the Gar-pike, scarcely ever exceeding a length of two feet. Some of the tropical species live in fresh water only; they are of small size and viviparous.

Arrhamphus.—Mouth formed as in Hemirhamphus, except that the lower jaw is not produced into a beak. Pectoral fins of moderate length.

One species (A. sclerolepis) from the coast of Queensland (not New Zealand); it may be regarded as a Hemirhamphus, with retarded development of the lower jaw.

Exocoetus.—Jaws short, intermaxillaries and maxillaries separate. Teeth minute, rudimental, and sometimes absent. Body moderately oblong, covered with rather large scales. Pectorals very long, an organ of flying.

Fig. 281.—Flying Fish; Exocoetus callopterus.

Forty-four different kinds of “Flying-fishes” are known from tropical and sub-tropical seas; some have a very wide range, whilst others seem to remain within one particular part of the ocean; thus, the species figured, E. callopterus, has been hitherto found on the Pacific side of the isthmus of Panama only. Their usual length is about 10 or 12 inches, but specimens of 18 inches have been caught. They always live in shoals, and their numbers at certain times and localities are immense; thus, at Barbadoes many boats engage in their capture, as they are excellent eating. The pectorals are in the various species of unequal length; in some they extend to the anal fin only; in others (and these are the best fliers) to the caudal. A few have curious, barbel-like appendages at the lower jaw, which may disappear with age or be persistent throughout life. The literature on the subject of Flying-fishes is very extensive, and great diversity of opinion exists among observers as regards the mode and power of their flight; but the most reliable agree that the fishes do not leave the water for the purpose of catching insects (!), and that they are unable to move their fins in the manner of a bat or bird, or to change voluntarily the direction of their flight, or to fly beyond a very limited distance. The most recent enquiries are those of K. Möbius (“Die Bewegungen der Fliegenden Fische durch die Luft,” Leip. 1878, 8vo), the chief results of which may be summed up thus: Flying-fish are more frequently observed in rough weather and in a disturbed sea than during calm; they dart out of the water when pursued by their enemies, or frightened by an approaching vessel, but frequently also without any apparent cause, as is also observed in many other fishes; and they rise without regard to the direction of the wind or waves. The fins are kept quietly distended, without any motion, except an occasional vibration caused by the air whenever the surface of the wing is parallel with the current of the wind. Their flight is rapid, but gradually decreasing in velocity, greatly exceeding that of a ship going 10 miles an hour, and a distance of 500 feet. Generally, it is longer when the fishes fly against than with or at an angle to the wind. Any vertical or horizontal deviation from a straight line is not caused at the will of the fish, but by currents of the air; thus they retain a horizontally straight course when flying with or against the wind, but are carried towards the right or left whenever the direction of the wind is at an angle with that of their flight. However, it sometimes happens that the fish during its flight immerses its caudal fin in the water, and by a stroke of its tail turns towards the right or left. In a calm the line of their flight is always also vertically straight, or rather parabolic, like the course of a projectile, but it may become undulated in a rough sea, when they are flying against the course of the waves; they then frequently overtop each wave, being carried over it by the pressure of the disturbed air. Flying-fishes often fall on board of vessels, but this never happens during a calm, or from the lee side, but during a breeze only, and from the weather side. In daytime they avoid a ship, flying away from it; but during the night, when they are unable to see, they frequently fly against the weather-board, where they are caught by the current of air, and carried upwards to a height of 20 feet above the surface of the water, while, under ordinary circumstances, they keep close to it. All these observations point clearly to the fact that any deflection from a straight course is due to external circumstances, and not to voluntary action on the part of the fish.

Tenth Family—Esocidæ.

Body covered with scales; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Adipose fin none; the dorsal fin belongs to the caudal portion of the vertebral column. Stomach without blind sac; pyloric appendages none. Pseudobranchiæ glandular, hidden; air-bladder simple; gill-opening very wide.

This family includes one genus only, Esox, the “Pikes,” inhabitants of the fresh waters of the temperate parts of Europe, Asia, and America. The European species, E. lucius, inhabits all three continents, but the North American waters harbour five, or perhaps more, other species, of which the “Muskellunge,” or “Maskinonge” (E. estor) of the Great Lakes attains to the same large size as the common Pike. The other species are generally called “Pickerell” in the United States.

Fig. 282.—The Pike. (Esox lucius.)

Fossil Pike, belonging to the existing genus, have been found in the freshwater-chalk of Oeningen, and in the diluvial marl of Silesia. Remains of the common Pike occur in abundance in quaternary deposits.

Eleventh Family—Galaxiidæ.

Body naked, barbels none. Margin of the upper jaw chiefly formed by the intermaxillaries, which are short, and continued by a thick lip, behind which are the maxillaries. Belly rounded; adipose fin none; dorsal opposite to anal. Pyloric appendages in small number. Air-bladder large, simple; pseudobranchiæ none. The ova fall into the cavity of the abdomen before exclusion.

Small freshwater fishes of the southern hemisphere, belonging to two genera, Galaxias and Neochanna. Of the former genus five species are found in New Zealand, where this type is most developed, three in New South Wales, two in Tasmania, and four in the southern extremity of South America. Their native name in New Zealand is “Kokopu,” and they were dignified with the name of “Trout” by the settlers before the introduction of true Salmonidæ. They rarely exceed a length of eight inches. Neochanna is a degraded form of Galaxias, from which it differs by the absence of ventral fins. This fish has hitherto been found only in burrows, which it excavates in clay or consolidated mud, at a distance from water.

Fig. 283.—Galaxias truttaceus, from Tasmania.

Twelfth Family—Mormyridæ.

Body and tail scaly; head scaleless; barbels none. The margin of the upper jaw is formed in the middle by the intermaxillaries, which coalesce into a single bone, and laterally by the maxillaries. Sub- and inter-operculum present, the latter very small. On each side of the single parietal bone a cavity leading into the interior of the skull, and covered with a thin bony lamella. All the fins are well developed, in Mormyrus; or caudal, anal, and ventral fins are absent, in Gymnarchus. No adipose fin. Pseudobranchiæ none; gill-openings reduced to a short slit. Air-bladder simple. Two coeca pylorica behind the stomach.

This family is characteristic of the freshwater fauna of tropical Africa. Of Mormyrus (including Hyperopisus and Mormyrops), fifty-one species are known, of which eleven occur in the Nile. Some attain a length of three or four feet, others remain small. Their flesh is said to have an excellent flavour. The species figured (and probably other allied species) was an object of veneration to the ancient Egyptians, and, therefore, frequently occurs in their emblematic inscriptions. They abstained from eating it because it was one of three different kinds of fishes accused of having devoured a member of the body of Osiris, which, therefore, Isis was unable to recover when she collected the rest of the scattered members of her husband.

Fig. 284.—Mormyrus oxyrhynchus.

The Mormyri possess a singular organ on each side of the tail, without electric functions, but evidently representing a transitional condition from muscular substance to an electric organ. It is an oblong capsule divided into numerous compartments by vertical transverse septa, and containing a gelatinous substance. The Mormyri differ much with regard to the extent of the dorsal and anal fins, the former sometimes occupying the greater portion of the length of the back, sometimes being much shorter and limited to the tail. In some the snout is short and obtuse, in others long and decurved, with or without appendage.

Of Gymnarchus one species only is known, G. niloticus, which occurs in the Nile and West African rivers, and attains a length of six feet. The form of its body is eel-like, and each jaw is armed with a series of incisor-like teeth. Like Mormyrus, Gymnarchus possesses a pseudo-electric organ, thickest on the tail, tapering in front, and extending nearly to the head. It consists of four membranaceous tubes intimately connected with the surrounding muscles, and containing prismatic bodies arranged in the manner of a paternoster. The air-bladder of Gymnarchus is cellular, very extensible, and communicates with the dorsal side of the œsophagus by a duct possessing a sphincter.

[See Erdl, Münchner Gelehrte Anzeigen, 1846, xxiii., and Hyrtl, Denkschr. Akad. Wiss. Wien. 1856. xii.]

Thirteenth Family—Sternoptychidæ.

Body naked, or with very thin deciduous scales; barbels none. Margin of the upper jaw formed by the maxillary and intermaxillary, both of which are toothed; opercular apparatus not completely developed. Gill-opening very wide; pseudobranchiæ present or absent; air-bladder simple, if present. Adipose fin present, but generally rudimentary. Series of phosphorescent bodies along the lower parts. The eggs are enclosed in the sacs of the ovarium, and excluded by oviducts.

Pelagic and Deep-sea fishes of small size.

Sternoptyx.—Trunk much elevated and compressed, with the trunk of the tail very short. Body covered with a silvery pigment, without regular scales; series of phosphorescent spots run along the lower side of the head, body, and tail. Cleft of the mouth wide, vertical, with the lower jaw prominent. Jaws armed with small teeth. Eyes rather large, and although lateral, directed upwards and placed close together. Ventral fins very small. A series of imbricate scutes runs along the abdomen, forming a kind of serrature. The dorsal fin is short, and occupies about the middle of the length of the fish; it is preceded by the first commencement of the formation of a spinous dorsal, several neural spines being prolonged beyond the dorsal muscle forming a triangular osseous plate. Adipose fin rudimentary; anal short; caudal forked.

These small fishes are now and then picked up in the Mediterranean and Atlantic. According to the dredging-records of the “Challenger,” they and the allied genera Argyropelecus and Polyipnus would descend to depths of respectively 1100 and 2500 fathoms; but the form of their body and their whole organisation render this statement very improbable; they most likely live at a small depth during the daytime, coming to the surface at night, like many Scopelus.

Coccia and Maurolicus are two other genera allied to the preceding.

Fig. 285.—Chauliodus sloanii.

Chauliodus.—Body elongate, compressed, covered with exceedingly thin and deciduous scales; series of luminous (phosphorescent) spots run along the lower side of the head, body, and tail. Head much compressed and elevated, with the bones thin, but ossified, and with the opercular portion very narrow, the interoperculum being rudimentary. Cleft of the mouth exceedingly wide, the intermaxillary forming one half of the upper jaw. Each intermaxillary with four long canine teeth; edge of the maxillary finely denticulated; mandible with pointed, widely set teeth, the anterior of which are exceedingly long; none of the large teeth are received within the mouth. Palatine with a single series of small pointed teeth; no teeth on the tongue. Eye of moderate size. Pectoral and ventral fins well developed. Dorsal fin anteriorly on the trunk, before the ventrals; adipose fin small, sometimes fimbriated; anal short, rather close to the caudal, which is forked. Gill-opening very wide, the outer branchial arch extending forward to behind the symphysis of the lower jaw; it has no gill-rakers. Branchiostegals numerous.

This genus, of which one species only (Ch. sloanii) is known, is generally distributed over the great depths of the oceans, and does not appear to be scarce; it attains to a length of 12 inches, and must be one of the most formidable fishes of prey of the deep-sea.

Allied genera are Gonostoma, Photichthys, and Diplophos, all of which have the teeth of much smaller size.

Fourteenth Family—Stomiatidæ.

Skin naked, or with exceedingly delicate scales; a hyoid barbel. Margin of the upper jaw formed by the intermaxillary and maxillary which are both toothed; opercular apparatus but little developed. Gill-opening very wide; pseudobranchiæ none. The eggs are enclosed in the sacs of the ovarium, and excluded by oviducts.

Deep-sea fishes, descending to the greatest depths, characterised by their barbel and their formidable dentition.

Fig. 286.—Astronesthes niger. The white spots in front of the eye are phosphorescent organs.

Some have two dorsal fins, the posterior of which is adipose; they belong to the genus Astronesthes, are the smallest of the family, and frequently met with in the Atlantic.

The others—viz. Stomias, Echiostoma, Malacosteus, and Bathyophis, lack the adipose fin, the rayed dorsal being opposite to the anal. Of these the one longest known is

Stomias.—Body elongate, compressed, covered with exceedingly fine and deciduous scales, which are scarcely imbricate, lying in subhexagonal impressions; vent situated at no great distance from the caudal fin. Head compressed, with the snout very short, and with the cleft of the mouth very wide. Teeth pointed, unequal in size, those of the intermaxillaries and of the mandible being the longest; maxillary finely denticulated; vomer with a pair of fangs; palatine bones and tongue with smaller pointed teeth. Eye of moderate size. Opercular portion of the head narrow. A fleshy barbel in the centre of the hyoid region. Dorsal opposite the anal, close to the caudal; pectoral and ventral fins feeble, the latter inserted behind the middle of the length of the body. Series of phosphorescent dots run along the lower side of the head, body, and tail. Gill-opening very wide. Pyloric appendages none.

Three species are known; beside specimens which were found floating on the surface, others have been dredged from depths varying between 450 and 1800 fathoms.

Fifteenth Family—Salmonidæ.

Body generally covered with scales; head naked; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Belly rounded. A small adipose fin behind the dorsal. Pyloric appendages generally numerous, rarely absent. Air-bladder large, simple; pseudobranchiæ present. The ova fall into the cavity of the abdomen before exclusion.

Inhabitants of the sea and freshwater; the majority of the marine genera are deep-sea forms. The freshwater forms are peculiar to the temperate and arctic zones of the Northern Hemisphere, one occurring in New Zealand; many freshwater species periodically or occasionally descending to the sea. One of the most valuable families of the class of fishes. No fossils of the freshwater forms are known; but of the marine genera, Osmerus occurs in the greensand of Ibbenbusen, and in the schists of Glaris and Licata; a species of Mallotus, indistinguishable from the living M. villosus, occurs abundantly in nodules of clay of unknown geological age in Greenland. Other genera, as Osmeroides, Acrognathus, and Aulolepis, from the chalk of Lewes, belong to the same fauna as species of Beryx, and were probably deep-sea Salmonoids.

Salmo.—Body covered with small scales. Cleft of the mouth wide, the maxillary extending to below or beyond the eye. Dentition well developed; conical teeth in the jaw bones, on the vomer and palatines, and on the tongue, none on the pterygoid bones. Anal short, with less than fourteen rays. Pyloric appendages numerous; ova large. Young specimens with dark cross-bands (Parr-marks).

We know of no other group of fishes which offers so many difficulties to the ichthyologist with regard to the distinction of the species as well as to certain points in their life-history, as this genus, although this may be partly due to the unusual attention which has been given to their study, and which has revealed an almost greater amount of unexplained facts than of satisfactory solutions of the questions raised. The almost infinite variations of these fishes are dependent on age, sex and sexual development, food, and the properties of the water. Some of the species interbreed, and the hybrids mix again with one of the parent species, thus producing an offspring more or less similar to the pure breed. The coloration is, first of all, subject to variation; and consequently this character but rarely assists in distinguishing a species, there being not one which would show in all stages of development the same kind of coloration. The young of all the species are barred; and this is so constantly the case that it may be used as a generic or even as a family character, not being peculiar to Salmo alone, but also to Thymallus and probably to Coregonus. The number of bars is not quite constant, but the migratory Trout have two (and even three) more than the River-Trout. In some waters River-trout remain small, and frequently retain the Parr-marks all their lifetime; at certain seasons a new coat of scales overlays the Parr-marks, rendering them invisible for a time; but they reappear in time, or are distinct as soon as the scales are removed. When the Salmones have passed this “Parr” state, the coloration becomes much diversified. The males, especially during and immediately after the spawning time, are more intensely coloured and variegated than the females; specimens which have not attained to maturity retaining a brighter silvery colour, and being more similar to the female fish. Food appears to have less influence on the coloration of the outer parts than on that of the flesh; thus the more variegated specimens are frequently out of condition, whilst well-fed individuals with pinkish flesh are of a more uniform though bright coloration. Chemistry has not supplied us yet with an analysis of the substance which gives the pink colour to the flesh of many Salmonoids; but there is little doubt that it is identical with, and produced by, the red pigments of many salt- and freshwater Crustaceans, which form a favourite food of these fishes. The water has a marked influence on the colours; Trout with intense ocellated spots are generally found in clear rapid rivers, and in small open Alpine pools; in the large lakes with pebbly bottom the fish are bright silvery, and the ocellated spots are mixed with or replaced by X-shaped black spots; in pools or parts of lakes with muddy or peaty bottom, the trout are of a darker colour generally, and when enclosed in caves or holes, they may assume an almost uniform blackish coloration.

The change of scales (that is, the rapid reproduction of the worn part of the scales) coincides in the migratory species with their sojourn in the sea. The renovated scales give them a bright silvery appearance, most of the spots disappearing or being overlaid and hidden by the silvery scales. Now, some of the species, like S. fario, inhabit all the different waters indicated, even brackish water, and, in consequence, we find a great variation of colour in one and the same species; others are more restricted in their habitat, like S. salar, S. ferox, etc., and, therefore, their coloration may be more precisely defined.

With regard to size the various species do not present an equal amount of variation. Size appears to depend on the abundance of food and the extent of the water. Thus, the Salmon and the different kinds of great Lake-trout do not appear to vary considerably in size, because they find the same conditions in all the localities inhabited by them. A widely spread species, however, like S. fario, when it inhabits a small mountain pool with scanty food, may never exceed a weight of eight ounces, whilst in a large lake or river, where it finds an abundance and variety of food, it attains to a weight of fourteen or sixteen pounds. Such large River-trout are frequently named and described as Salmon-trout, Bull-trout, etc. Further, in Salmones, as in the majority of fishes and tailed Batrachians, there is an innate diversity of growth in individuals hatched from the same spawn. Some grow rapidly and normally, others more slowly, and some remain dwarfed and stationary at a certain stage of development.

The proportions of the various parts of the body to one another vary exceedingly in one and the same species. Beside the usual changes from the young to the sexually mature form observed in all fishes, the snout undergoes an extraordinary amount of alteration of shape. In the mature male the intermaxillaries and the mandible are produced in various degrees, and the latter is frequently more or less bent upwards. Hence the males have the snout much more pointed and produced, and the entire head longer, than the females; with the intermaxillary bone the teeth, with which it is armed, are also enlarged, sometimes to four times the size of those of the females. And if this development of the front part of the head happens to be going on while the individual is able to obtain only a scanty supply of food, the usual proportions of the head and trunk are so altered that the species is very difficult to recognise. Barren male fish approach the females in the proportions of the head and body, but hybrid fishes do not differ in this respect from their parents. The abundance or scarcity of food, and the disposition or indisposition of the Salmonoids to feed, are other causes affecting the growth or fulness of the various parts of the body. In well-fed fishes the head is proportionally not only smaller but also shorter, and vice versa.

The fins vary to a certain degree. The variation in the number of the rays is inconsiderable and of no value for specific distinction. The caudal fin undergoes considerable changes of form with age, and dependency upon the sexual development. Young specimens of all species have this fin more or less deeply excised, so that the young of a species which has the caudal emarginate throughout life, is distinguished by a deeper incision of the fin, from the young of a species which has it truncate in the adult state. As the individuals of a species do not all attain to maturity at the same age and at the same size, and as mature individuals generally have the caudal less deeply excised than immature ones of the same age and size, it is evident that the variations in the form of the caudal are considerable and numerous, and that it is a very misleading character if due regard be not paid to the age and sexual development of the fish. Further, species inhabiting rapid streams as well as still waters show considerable variations in the form and length of all the fins; those individuals which live in rapid streams, being in almost constant motion and wearing off the delicate extremities of the fins, have the fin-rays comparatively shorter and stouter, and the fins of a more rounded form, particularly at the corners, than individuals inhabiting ponds or lakes. Moreover, one and the same individual may pass a part of its life in a lake, and enter a river at certain periods, thus changing the form of its fins almost periodically.

Finally, to complete our enumeration of these variable characters, we must mention that in old males, during and after the spawning-season, the skin on the back becomes thickened and spongy, so that the scales are quite invisible, being imbedded in the skin.

---

After this cursory review of variable characters we pass on to those which are more constant, not subject to ready modification by external circumstances; and which, therefore, ought to be noticed in every description of a species of Salmo.

1. The form of the præoperculum of the adult fish. The præoperculum is composed of a vertical (posterior) and horizontal (lower) part (limb), both meeting at a more or less rounded angle. The development of the lower limb is a very constant character; in some species (as in the Salmon) it is long, in others (S. ferox, S. brachypoma) exceedingly short. The adjoining woodcuts will readily show this difference.

Fig. 287.—Præoperculum of A. Salmo salar; B. Salmo brachypoma.

In young specimens of all Salmonoids the præoperculum has a very short lower limb; but whilst in some species it lengthens with age, its development in a horizontal direction is arrested in others.

2. The width and strength of the maxillary of the adult fish.—To show this character in two distinct species, we have given woodcuts of the maxillaries of females (12 inches long) of S. fario and S. levenensis of the same size.

Fig. 288.—Maxillary of A. Salmo fario; B. Salmo levenensis.

In young specimens of all Salmonoids the maxillary is comparatively shorter and broader, somewhat resembling that of Coregonus; yet this bone offers a valuable character for the determination of the young of some species; for instance, in a young S. cambricus it extends scarcely to below the centre of the eye, whilst in S. fario of the same size it reaches to, or even beyond, this point.

Fig. 289.—Vomerine teeth of Salmo salar (Salmon). A. Side view. B. Lower view.

3. The size of the teeth, those of the intermaxillaries excepted.

4. The arrangement, and the permanence or deciduousness of the vomerine teeth.—In some species the vomer is normally armed with a double or single series throughout life, although, of course, some of the teeth are frequently accidentally lost; in others, these teeth disappear gradually with age, the hinder ones first, so that finally the anterior only remain. In order to ascertain the arrangement of the teeth, it is necessary to remove the gengiva. Frequently the teeth stand in a distinctly double or single series, or they are placed alternately; but frequent irregularities occur which render the character vague, or even unsafe, so that some zoologists have rejected it entirely as unreliable. However, when a greater number of individuals really belonging to the same species are examined, a pretty safe conclusion may be arrived at as regards the arrangement of the teeth.

Fig. 290.—Vomerine teeth of Salmo fario, lower view.

Fig. 291.—Vomerine teeth of a Charr, side view.

5. The form of the caudal fin in specimens of a given size, age, and sexual development.

6. A great development of the pectoral fins, when constant in individuals from the same locality.

7. The size of the scales, as indicated by the number of transverse rows above the lateral line: one of the most constant characters.

8. The number of vertebræ.—Considering the great number of vertebræ in Salmonoids the constancy of this character is truly surprising. An excess or a diminution of the normal number by two, is of rare occurrence, and generally to be explained by the fact that one vertebra has been abnormally divided into two, two such vertebræ being considerably smaller than the others; or, on the other hand, that two have merged into one centrum, which is then unusually large, and provided with two neural spines. We have seen one case only, in which three vertebræ were united. The number of vertebræ can be easily ascertained in specimens destined for preservation in spirits, by an incision made along one side of the fish, a little above the lateral line.

9. The number of pyloric appendages.—There can be no doubt that this character may materially assist in fixing a species. We shall see that in some species it varies from 30 to 50; but in others, as in the Salmon and Charr, it has been found very constant (see Fig. [56], p. 131). If unexpected variations occur, their cause may be found in a partial confluence of the cæca, as we have observed that specimens of S. levenensis (a species normally with from 70 to 90 cæca), had those appendages of unusual width when the normal number was diminished.

---

We have mentioned above that many points in the life-history of the Salmonoids still remain very obscure:—

1. Johnson, a correspondent of Willughby (“Hist. Pisc.,” p. 194), had already expressed his belief that the different Salmonoids interbreed; and this view has since been shared by many who have observed these fishes in nature. Hybrids between the Sewin (S. cambricus) and the River Trout (S. fario) were numerous in the Rhymney and other rivers of South Wales, before Salmonoids were almost exterminated by the pollutions allowed to pass into those streams, and so variable in their characters that the passage from one species to the other could be demonstrated in an almost unbroken series, which might induce some naturalists to regard both species as identical. Abundant evidence of a similar character has accumulated, showing the frequent occurrence of hybrids between S. fario and S. trutta; hybrids between S. fario and species of Charr have been abundantly bred by continental pisciculturists. In some rivers the conditions appear to be more favourable to hybridism than in others, in which hybrids are of comparatively rare occurrence. Hybrids between the Salmon and some other species are very scarce everywhere. The hybrids are sexually as much developed as the pure breed, but nothing whatever is known of their further propagation and progeny.

2. Siebold has shown that some individuals of every species are not sexually developed, and that such individuals differ also externally from those normally developed. However, he appears to have gone too far when he stated that this state of sterility extends over the whole existence of such individuals, and that, therefore, the external peculiarities also remain permanent throughout life. According to Widegren this sterility is merely a temporary immaturity, and a part of the individuals arrive at a full sexual development at a later or much later period than others. To this we may add that many Salmonoids cease to propagate their species after a certain age, and that all so called overgrown individuals (that is, specimens much exceeding the usual size of the species) are barren. Externally they retain the normal specific characters.

The Salmon offers a most remarkable instance of irregularity as regards the age at which the individuals arrive at maturity. Shaw has demonstrated, in the most conclusive manner, that those small Salmonoids, which are generally called Parr, are the offspring of the Salmon, and that many males, from 7 to 8 inches long, have their sexual organs fully developed, and that their milt has all the impregnating properties of the seminal fluid of a much older and larger fish. That this Parr is not a distinct species—as has been again maintained by Couch—is further proved by the circumstance that these sexually mature Parr are absolutely identical in their zoological characters with the immature Parr, which are undoubtedly young Salmon, and that no Parr has ever been found with mature ova. But whether these Parr produce normal Salmon, impregnating the ova of female salmon, or mingle with the River-trout, or whether they continue to grow and propagate their species as fully developed Salmon, are questions which remain to be answered. We may only add that, as far as we know, barren old Salmon are extremely scarce.

3. The question whether any of the migratory species can be retained by artificial means in fresh water, and finally accommodate themselves to a permanent sojourn therein, must be negatived for the present. Several instances of successful experiments made for this purpose have been brought forward; but all these accounts are open to serious doubts, inasmuch as they do not afford us sufficient proof that the young fish introduced into ponds were really young migratory Salmonoids, or that the full-grown specimens were identical with those introduced, and not hybrids or non-migratory Trout of a somewhat altered appearance in consequence of the change of their locality. We have seen the experiment tried at two places in South Wales, and in both cases the Salmon and the pure Sewin died when not allowed to return to the sea. On the other hand, hybrid fishes from the Sewin and the Trout survived the experiment, and continued to grow in a pond perfectly shut up from communication with the sea. In that locality neither those hybrids nor the trout spawn.

4. Although the majority of the mature individuals of a migratory species ascend a river at a certain fixed time before the commencement of spawning, others enter the freshwater at a much earlier period, either singly or in small troops; and many appear to return to the sea before they reascend at the time of the regular immigration. It is not improbable that one and the same individual may change the salt- or freshwater several times in the year. However, this is the case in certain rivers only, for instance, in those falling into the Moray Firth; in others one immigration only is known to occur. The cause of the irregular ascents previous to the autumnal ascents is unknown. A part, at least, of the hybrid fishes retain the migratory instinct; but it is not known whether sterile individuals accompany the others in their migrations.

5. It is said that the migratory species invariably return to the river in which they are bred. Experiments have shown that this is normally the case; but a small proportion appear to stray so far away from their native place as to be unable to find their way back. Almost every year Salmon and Sea-trout in the Grilse-state make their appearance at the mouth of the Thames (where the migrating Salmonoids have become extinct for many years), ready to reascend and to restock this river as soon as its poisoned water shall be sufficiently purified to allow them a passage.

6. There has been much dispute about the time required for the growth of Salmonoids. The numerous and apparently contradictory observations tend to show that there is a great amount of variation even among individuals of the same origin living under the same circumstances, some of them growing much more quickly than others, and being ready to descend to the sea twelve months before their brethren. The cause of this irregularity is not explained. On the other hand, when we consider the fibrous condition of the Salmonoid skeleton, which is much less solid, and more wanting in calcareous substance, than that of the majority of Teleosteous fishes, we shall be quite prepared to adopt the truth of the observation that the young Salmonoids return to the fresh water, after a few months sojourn in the sea, and after having feasted on nourishing Crustaceans, Sand-eels, etc., with their former weight in ounces increased to pounds.

7. Liability to variation in form indicates that an animal can adapt itself to a variety of circumstances; therefore, such species as show the greatest pliability in this respect, are those which most recommend themselves for domestication and acclimatisation within certain climatic limits. Thus, the River-trout or Sea-trout were very proper subjects for those eminently successful attempts to establish them in similar latitudes of the Southern Hemisphere, whilst the attempt of transferring them into the low hill-streams of India ended (as could be foreseen) in a total failure. Those two species must now be considered to be fully acclimatised in Tasmania and New Zealand, and with but little protection may be expected to hold their own in the freshwaters of those colonies. Whether the acclimatisation of the Salmon will be in the end equally and permanently successful, remains to be seen. The true S. salar is not subject to variation, and is very sensitive to any change of external conditions, and to every kind of interference with its economy. The fourth species, with which attempts of acclimatisation in Southern Australia have been made, is a migratory Salmon from the Sacramento river in California. This experiment is still in progress, and believed to be promising of success. It will be a most curious problem to ascertain, how much the original characters and habits of those species will be affected by their transference to so distant a part of the globe. At present it would be too hazardous to offer an opinion on this point, especially as it is a fact that numerous cross-breeds have been introduced into, and reared in, Tasmania, which must more or less interfere with the characters of the pure breeds.

It is apparent, from the foregoing remarks, that the distinction of the various species of Salmonidæ is a matter of considerable difficulty, and that there is scope for great diversity of opinion. At any rate it is only by a close, long-continued study, and constant comparison of specimens of various ages and from various localities, that one is enabled to find a guide through the labyrinth of confusing variations. However, it is a significant fact that the very same characters by which we are enabled to distinguish European species occur again, though in an exaggerated form, in American Salmonoids (which everybody will admit to be of distinct species), and therefore our faith in them necessarily becomes strengthened. In accordance with acknowledged principles in zoology, forms which differ from their congeners by a combination of two or more of constant characters, are to be distinguished under distinct specific names. Most likely they have been derived, at a not very remote period, from common ancestors, but the question of their specific distinctness is no more affected by this consideration than the question whether Salmo and Coregonus are distinct genera. Whenever the zoologist observes two forms distinguished by peculiarities of organisation, such as cannot be conceived to be the effects of an external or internal cause, disappearing with the disappearance of that cause, and which forms have been propagated and are being propagated uniformly through all the generations within the limits of our observations, and are yet most probably to be propagated during the existence of mankind, he is obliged to describe these forms as distinct, and they will commonly be called species.

The species of the genus Salmo are inhabitants of the temperate and arctic zones of the Northern Hemisphere; the species are most abundant in the northern parts of the temperate zone, becoming scarcer beyond the Arctic circle, and in the warmer parts towards the south. The southernmost points in which Salmones are found, are, on the American continent, the rivers falling into the head of the Californian Gulf, and in the Old World the mountain rivers of the Atlas and Hindu Kush. The Salmones from those localities are migratory Trout in the New World, non-migratory and small in the Old. Those species which range to the highest latitudes (lat. 82°) belong to the division of Charr, a group which generally are more intolerant of a moderate temperature, than real Trout. The genus is subdivided into

a. Salmones—Salmon and Trout—with teeth on the body of the vomer as well as its head (see Figs. [289] and [290]).

b. Salvelini—Charr—with teeth on the head of the vomer only (see Fig. [291]).

Fig. 292.—Salmo brachypoma.

Of the host of species (the majority of which is unfortunately very insufficiently characterised) we enumerate the following:—[45]

a. Salmones.

1. S. salar (Salmon; Lachs or Salm; Saumon) (Fig. [6], p. 43). The Salmon can generally be readily recognised, but there are instances in which the identification of specimens is doubtful, and in which the following characters (besides others) will be of great assistance. The tail is covered with relatively large scales, there being constantly eleven, or sometimes twelve in a transverse series running from behind the adipose fin forwards to the lateral line, whilst there are from thirteen to fifteen in the different kinds of Sea-trout and River-trout. The number of pyloric appendages (see Fig. [56], p. 131) is great, generally between 60 and 70, more rarely falling to 53 or rising to 77. The body of the vomer is armed with a single series of small teeth, which at an early age are gradually lost from behind towards the front, so that half-grown and old individuals have only a few (1–4) left. The Salmon inhabits temperate Europe southwards to 43° N. lat., and is not found in any of the rivers falling into the Mediterranean. In the New World its southern boundary is 41° N. lat.

2. S. trutta (Sea-trout, Salmon-trout).[46]—Especially numerous in North Britain.

3. S. cambricus (Sewin).—Wales, South of England, Ireland, Norway, and Denmark.

4. S. fario (Common River-trout).

5. S. macrostigma (Algeria).

6. S. lemanus (Lake of Geneva).

7. S. brachypoma.—A migratory species from the rivers Forth, Tweed, and Ouse.

8. S. gallivensis (Galway Sea-trout).

9. S. orcadensis.—A non-migratory trout from Lough Stennis, in the Orkney Islands.

10. S. ferox.—The great Lake-trout of North Britain, Wales, and Ireland.

11. S. stomachicus (the Gillaroo of Ireland).

12. S. nigripinnis from mountain-pools of Wales.

13. S. levenensis (Lochleven Trout).

14. S. oxi from the rivers of the Hindu Kush.

15. S. purpuratus from the Pacific coast of Asia and North America.

16. S. macrostoma.—Japan.

17. S. namaycush.—The great Lake-trout of North America.

b. Salvelini: Charr.

1. S. umbla.—The “Ombre chevalier” of the Swiss lakes.

2. S. salvelinus.—The “Sælbling” of the Alpine lakes of Bavaria and Austria.

3. S. alpinus.—The common Northern Charr, growing to a length of four feet, and migratory.

4. S. killinensis.—The Loch Killin Charr, Inverness-shire.

5. S. willughbii.—The Loch Windermere Charr.

6. S. perisii.—The “Torgoch” of Wales.

7. S. grayi.—The “Freshwater Herring” of Lough Melvin, Ireland.

8. S. colii.—Charr of Loughs Eske and Dan.

9. S. hucho.—The “Huchen” of the Danube, growing to the size of the Salmon.

10. S. alipes from lakes in Boothia Felix and Greenland.

11. S. arcturus.—The most northern species from 82° lat.

12. S. fontinalis.—The common “Brook-trout” of the United States.

13. S. oquassa.—A lake species from the State of Maine.

Oncorhynchus differs from Salmo only in the increased number of anal rays, which are more than fourteen. All the species are migratory, ascending American and Asiatic rivers flowing into the Pacific. The Californian Salmon (O. quinnat?) belongs to this genus.

Other allied genera are Brachymystax and Luciotrutta.

Plecoglossus.—Body covered with very small scales. Cleft of the mouth wide; maxillary long. Dentition feeble; intermaxillaries with a few small, conical, pointed teeth; the teeth of the maxillaries and mandibles are broad, truncated, lamellated and serrated, movable, seated in a fold of the skin. The mandibles terminate each in a small knob, and are not jointed at the symphysis. The mucous membrane in the interior of the mouth—between the terminal halves of the mandibles—forms a peculiar organ, being raised into folds, with a pair of pouches in front and a single one behind. Tongue very small, with minute teeth, its apical part being toothless; palate apparently without teeth.

A small aberrant form of Freshwater-Salmonoids abundantly found in Japan and the Island of Formosa.

Osmerus.—Body covered with scales of moderate size. Cleft of the mouth wide; maxillary long, extending to, or nearly to, the hind margin of the orbit. Dentition strong; intermaxillary and maxillary teeth small, much smaller than those of the mandible. Vomer with a transverse series of teeth, several of which are large, fang-like; a series of conical teeth along the palatine and pterygoid bones. Tongue with very strong fang-like teeth anteriorly, and with several longitudinal series of smaller ones posteriorly. Pectoral fins moderately developed. Pyloric appendages very short, in small number; ova small.

The “Smelt” (O. eperlanus) is common on many places of the coasts of Northern Europe and America. In the sea it grows to a length of eight inches; but, singularly, it frequently migrates from the sea into rivers and lakes, where its growth is very much retarded. That this habit is one of very old date, is evident from the fact that this small freshwater form occurs, and is fully acclimatised in lakes which have now no open communication with the sea. And still more singularly, this same habit, with the same result, has been observed in the Smelt of New Zealand (Retropinna richardsonii). The Smelt is considered a delicacy in Europe, as well as in America, where the same species occurs. Two other allied genera, Hypomesus and Thaleichthys, are found on the Pacific coast of North America, the latter being caught in immense numbers, and known by the name “Eulachon” and “Oulachan;” it is so fat, that it is equally used as food and as candle.

Mallotus.—Body covered with minute scales, which are somewhat larger along the lateral line and along each side of the belly; in mature males these scales become elongate, lanceolate, densely tiled, with free projecting points, forming villous bands. Cleft of the mouth wide; maxillary very thin, lamelliform, extending to below the middle of the eye. Lower jaw the longer, partly received between the maxillaries. Dentition very feeble; the teeth forming single series; only the teeth on the tongue are somewhat larger and disposed in an elliptical patch. Pectoral fins large, horizontal, with broad base. Pyloric appendages very short, in small number; ova small.

The “Capelin” (M. villosus) is found on the Arctic coasts of America and of Kamtschatka. It is caught in immense numbers by the natives, who consume it fresh, or dry it for use in the winter. Its length does not exceed nine inches.

Coregonus.—Body covered with scales of moderate size. Cleft of the mouth small; maxillary broad, short or of moderate length, not extending behind the orbit. Teeth, if present, extremely minute and deciduous. Dorsal fin of moderate length; caudal deeply forked. Ova small.

Fig. 293.—Coregonus oxyrhynchus.

Fig. 294.—Head of Coregonus oxyrhynchus.

The majority of the species, of which more than forty are known, are lacustrine species; and comparatively few are subject to periodical migrations to the sea, like Salmo. They are confined to the northern parts of temperate Europe, Asia, and North America. Their distribution is local, but sometimes three and more species are found in the same lake. They abound in every lake and river of the northern parts of North America, and are known by the name of “White-fish.” They are of vital importance to some tribes of the native population. The European C. oxyrhynchus is as much a marine as a freshwater species. In the British Islands several small species occur, viz. C. clupeoides, the “Gwyniad,” “Schelly,” or “Powen” from the great lakes; C. vandesius, the “Vendace” of Lochmaben; and C. pollan, the “Pollan” of the Irish lakes. The latter is brought in quantities to Belfast market during the season, that is, at the time when it rises from the depths of Lough Neagh to deposit its spawn near the shore. Thomson says that in September 1834 some 17,000 were taken there at three or four draughts of the net. Some of the species of the continent of Europe and America attain to a much larger size than the British species, viz. to a length of two feet.

Fig. 295.—Coregonus clupeoides.

Thymallus.—Principally distinguished from Coregonus by its long many-rayed dorsal fin.

“Graylings”—five species, inhabiting clear streams of the north of Europe, Asia, and North America. The best known are the “Poisson bleu” of the Canadian voyageurs (Th. signifer), and the European Grayling (T. vulgaris).

Salanx.—Body elongate, compressed, naked or covered with small, exceedingly fine, deciduous scales. Head elongate and much depressed, terminating in a long, flat, pointed snout. Eye small. Cleft of the mouth wide; jaws and palatine bones with conical teeth, some of the intermaxillaries and mandibles being enlarged; no teeth on the vomer; tongue with a single series of curved teeth. Dorsal fin placed far behind the ventrals, but in front of the anal; anal long; adipose fin small; caudal forked. Pseudobranchiæ well developed; air-bladder none. The entire alimentary canal straight, without bend; pyloric appendages none. Ova small.

This small, transparent, or whitish fish (S. chinensis) is well known at Canton and other places of the coast of China as “White-bait,” and considered a delicacy. It is evidently a fish which lives at a considerable depth in the sea, and approaches the coast only at certain seasons.

Finally, this family is represented in the deep sea by three genera, Argentina, Microstoma, and Bathylagus, of which the two former live at moderate depths, and have been known for a long time, whilst the last was discovered during the “Challenger” expedition in the Atlantic and Antarctic Oceans at depths of 1950 and 2040 fathoms. As Argentina is sometimes found in the North Atlantic, and even near the British coasts, we give its principal characters.

Argentina.—Scales rather large; cleft of the mouth small; intermaxillaries and maxillaries very short, not extending to below the orbit. Eye large. Jaws without teeth; an arched series of minute teeth across the head of the vomer and on the fore part of the palatines; tongue armed with a series of small curved teeth on each side. Dorsal fin short, in advance of the ventrals; caudal deeply forked. Pseudobranchiæ well developed. Pyloric appendages in moderate numbers. Ova small.

Four species are known, of which A. silus and A. hebridica have been found occasionally on the North British, and, more frequently, on the Norwegian coast. The other species are from the Mediterranean. Attaining to a length of 18 inches.

Sixteenth Family—Percopsidæ.

Body covered with ctenoid scales; head naked. Margin of the upper jaw formed by the intermaxillaries only; opercular apparatus complete. Barbels none. Gill-openings wide. Adipose fin present.

One genus and species only (Percopsis guttatus); interesting as having the general characters of Salmonoids, but the mouth and scales of a Percoid. Freshwaters of the northern United States.

Seventeenth Family—Haplochitonidæ.

Body naked or scaly (cycloid). Margin of the upper jaw formed by the intermaxillary; opercular apparatus complete. Barbels none. Gill-opening wide; pseudobranchiæ. Air-bladder simple. Adipose fin present. Ovaries laminated; the eggs fall into the cavity of the abdomen, there being no oviduct. Pyloric appendages none.

Fig. 296.—Prototroctes oxyrhynchus, New Zealand.

Freshwater-fishes which represent the Salmonoids in the southern hemisphere. Two genera only are known. Haplochiton (Fig. [104], p. 250) abundant in lakes and the streams falling into the Straits of Magelhæn and in the rivers of Chile and the Falkland Islands. It has the general appearance of a Trout, but is naked. Prototroctes, with the habit of a Coregonus, scaly, and provided with minute teeth; one species (P. maræna) is common in South Australia, the other (P. oxyrhynchus) in New Zealand. The settlers in these colonies call them Grayling; the Maori name of the second species is “Upokororo.”

Eighteenth Family—Gonorhynchidæ.

Head and body entirely covered with spiny scales; mouth with barbels. Margin of the upper jaw formed by the intermaxillary, which, although short, is continued downwards as a thick lip, situated in front of the maxillary. Adipose fin none; the dorsal fin is opposite to the ventrals, and short, like the anal. Stomach simple, without blind sac; pyloric appendages in small number. Pseudobranchiæ; air-bladder absent. Gill-openings narrow.

Fig. 297.—Gonorhynchus greyi.

Fig. 298.—Scale of Gonorhynchus greyi.

One genus and species only (Gonorhynchus greyi) is known; it is a semi-pelagic fish, not very rare off the Cape of Good Hope, and in the Australian and Japanese seas. From 12 to 18 inches long. The colonists in New Zealand name it “Sand-eel,” as it frequents bays with sandy bottom. It is eaten.

Nineteenth Family—Hyodontidæ.

Body covered with cycloid scales; head naked; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally, the latter being articulated to the end of the former. Opercular apparatus complete. Adipose fin none; the dorsal fin belongs to the caudal portion of the vertebral column. Stomach horseshoe-shaped, without blind sac; intestine short; one pyloric appendage. Pseudobranchiæ none; air-bladder simple. Gill-openings wide. The ova fall into the abdominal cavity before exclusion.

One genus and species only (Hyodon tergisus) is known, generally called “Moon-eye.” It is abundant in the western streams and great lakes of North America. From 12 to 18 inches long.

Twentieth Family—Pantodontidæ.

Body covered with large cycloid scales; sides of the head osseous. Margin of the upper jaw formed by the single intermaxillary mesially, and by the maxillaries laterally. The dorsal fin belongs to the caudal portion of the vertebral column, is short, opposite and similar to the anal. Gill-openings wide; gill-covers consisting of a præoperculum and operculum only. Branchiostegals numerous. Pseudobranchiæ none; air-bladder simple. Stomach without coecal sac; one pyloric appendage. Sexual organs with a duct.

A small freshwater-fish (Pantodon buchholzi), singularly alike to a Cyprinodont, from the west coast of Africa.

Twenty-first Family—Osteoglossidæ.

Body covered with large hard scales, composed of pieces like mosaic. Head scaleless; its integuments nearly entirely replaced by bone; lateral line composed of wide openings of the mucus-duct. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. The dorsal fin belongs to the caudal portion of the vertebral column, is opposite and very similar to the anal fin; both approximate to the rounded caudal (with which they are abnormally confluent). Gill-openings wide; pseudobranchiæ none; air-bladder simple or cellular. Stomach without coecal sac; pyloric appendages two.

Large freshwater-fishes of the tropics, whose singular geographical distribution has been noticed above (p. 223).

Osteoglossum.—Cleft of the mouth very wide, oblique, with the lower jaw prominent. A pair of barbels at the lower jaw. Abdomen trenchant. Bands of rasp-like teeth on the vomer, palatine and pterygoid bones, on the tongue and hyoid. Pectoral fins elongate.

O. bicirrhosum from Brazil and Guyana, O. formosum from Borneo and Sumatra, O. leichardti from Queensland.

Arapaima.—Cleft of the mouth wide, with the lower jaw prominent; barbels none. Abdomen rounded. Jaws with an outer series of small conical teeth; broad bands of rasp-like teeth on the vomer, palatines, pterygoids, sphenoid, os linguale, and hyoid. Pectoral fins of moderate length.

Fig. 299.—Arapaima gigas.

The largest freshwater Teleostean known, exceeding a length of 15 feet and a weight of 400 pounds. It is common in the large rivers of Brazil and the Guyanas, and esteemed as an article of food. When salted it is exported in large quantities from the inland fisheries to the seaports.

Heterotis.—Cleft of the mouth rather small, with the jaws subequal; barbels none. A single series of small teeth in the jaws; pterygoids and hyoid with a patch of small conical teeth; none on the vomer or palatines.

This fish (H. niloticus), which is not uncommon in the Upper Nile and the West African rivers, exhibits several anatomical peculiarities. The fourth branchial arch supports a spiral accessory organ, the function of which is still unexplained. The air-bladder is cellular, and the stomach consists of a membranous and a muscular portion.

Twenty-Second Family—Clupeidæ.

Body covered with scales; head naked; barbels none. Abdomen frequently compressed into a serrated edge. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally; maxillaries composed of at least three movable pieces. Opercular apparatus complete. Adipose fin none. Dorsal not elongate; anal sometimes very long. Stomach with a blind sac; pyloric appendages numerous. Gill-apparatus much developed, the gill-openings being generally very wide. Pseudobranchiæ generally present. Air-bladder more or less simple.

The family of “Herrings” is probably unsurpassed by any other in the number of individuals, although others comprise a much greater variety of species. The Herrings are principally coast-fishes, or, at least, do not go far from the shore; none belong to the deep-sea fauna; scarcely any have pelagic habits, but many enter or live in fresh waters communicating with the sea. They are spread over all the temperate and tropical zones. Fossil remains of Herrings are numerous, but the pertinence of some of the genera to this family is open to serious doubts, as the remains are too fragmentary to allow of determining whether they belong to Salmonoids or Clupeoids. Therefore, Agassiz comprised both families in one—Halecidæ. Many of the remains belong to recent genera, which are readily recognised, as Clupea, Engraulis and Chanos, principally from the schists of Glaris and Licata, from Monte Bolca and the Lebanon. Others, like Thrissopater, from the Gault at Folkestone, Leptosomus, Opisthopteryx, Spaniodon, from the chalk and tertiary formations, can be readily associated with recent genera. But the majority do not show an apparent affinity to the present fauna. Thus, Halec from the chalk of Bohemia, Platinx and Coelogaster from Monte Bolca, Rhinellus from Monte Bolca and Mount Lebanon, Scombroclupea, with finlets behind the anal, from the Lebanon and Comen, and Crossognathus from tertiary Swiss formations, allied to Megalops, Spathodactylus from the same locality, and Chirocentrites from Mount Lebanon, etc. Finally, a genus recently discovered in tertiary formations of Northern Italy, Hemitrichas, has been classed with the Clupeoids, from which, however, it differs by having two short dorsal fins, so that it must be considered, without doubt, to be the representative of a distinct family.

Engraulis (including Cetengraulis).—Scales large or of moderate size. Snout more or less conical, projecting beyond the lower jaw. Teeth small or rudimentary. Intermaxillaries very small, hidden; maxillary long, attached to the cheek by a scarcely distensible membrane. Anal fin of moderate or great length. Branchiostegals short, from nine to fourteen in number.

Not less than forty-three different species of “Anchovies” are known from temperate and tropical seas. They exhibit marked differences in the length of their maxillary bone, which sometimes does not reach the gill-opening, whilst in other species it extends far beyond it; and in the number of their anal rays, which varies from 20 to 80. Some have the upper pectoral ray prolonged into a filament, thus leading towards the succeeding genus, Coilia. The majority are recognised, besides, by their peculiar structure, by a broad silvery, lateral band, similar to that observed in the Atherines. The most celebrated Anchovy is E. encrasicholus, very plentiful in the Mediterranean, but rarely wandering northwards. It is the species which, preserved in salt, is exported to all parts of the world, although similarly lucrative fisheries of Anchovies might be established in Tasmania where the same species occurs, in Chile, China, Japan, California, at Buenos Ayres, each of which countries possesses Anchovies by no means inferior to the Mediterranean species.

Coilia.—Body terminating in a long tapering tail. Scales of moderate size. Snout and jaws as in Engraulis. Anal fin exceedingly long, confluent with the caudal. The two or three upper pectoral rays are much prolonged, and their branches form four, six, or seven filaments.

Fig. 300.—Coilia clupeoides.

Ten species from Indian and Chinese seas.

Chatoëssus.—Body compressed; abdomen serrated. Scales of moderate size. Snout obtuse, or obtusely conical, more or less projecting beyond the cleft of the mouth, which is narrow, more or less transverse. Maxillary joined to the ethmoid, its upper portion being behind the intermaxillary. Teeth none. Anal fin rather long; dorsal opposite to the ventrals, or to the space between ventrals and anal. Gill-membranes entirely separate; branchial arches forming two angles, one pointing forward and the other backwards; the fourth branchial arch with an accessory organ; branchiostegals of moderate length, five or six in number.

Ten species from the coasts, brackish and fresh waters of Central America (one species ranges to New York), Australia, the East Indies, and Japan.

Clupea.—Body compressed, with the abdomen serrated, the serrature extending forwards to the thorax. Scales of moderate or large, rarely of small size. Upper jaw not projecting beyond the lower. Cleft of the mouth of moderate width. Teeth, if present, rudimentary and deciduous. Anal fin of moderate extent, with less than thirty rays; dorsal fin opposite to the ventrals. Caudal forked.

This genus comprises more than sixty different species, the geographical distribution of which coincides with that of the family. The majority are of greater or less utility to man, but a few tropical species (C. thrissa, C. venenosa, and others) acquire, probably from their food, highly poisonous properties, so as to endanger the life of persons eating them. The most noteworthy species are—

1. C. harengus (the “Herring”).—It is readily recognised by having an ovate patch of very small teeth on the vomer. D. 17–20. A. 16–18. L. lat. 53–59. Vert. 56. Gill-cover smooth, without radiating ridges. It inhabits, in incredible numbers, the German Ocean, the northern parts of the Atlantic, and the seas north of Asia. The Herring of the Atlantic coasts of North America is identical with that of Europe. A second species has been supposed to exist on the British coast (C. leachii), but it comprises only individuals of a smaller size, the produce of an early or late spawn. Also the so-called “White-bait” is not a distinct species, but consists chiefly of the fry or the young of herrings, and is obtained “in perfection” at localities where these small fishes find an abundance of food, as in the estuary of the Thames.

[Separate accounts on the Herring may be found in Cuvier and Valenciennes, “Hist. nat. des Poissons,” vol. xx.; J. M. Mitchell, “The Herring, its Natural History and National Importance,” Edinb. 1864, 8vo; P. Neucrantz, “De Harengo,” Lübeck, 1654; J. S. Dodd, “Essay towards a Natural History of the Herring,” Lond. 1768, 8vo; Bock, “Versuch einer vollstændigen Natur-und Handels-Geschichte des Hærings,” Königsberg, 1769, 8vo.]

2. C. mirabilis.—The Herring of the North Pacific.

3. C. sprattus.—The “Sprat.” Without vomerine teeth. D. 15–18. A. 17–20. L. lat. 47–48. Vert. 47–49. Gill-cover, smooth, without radiating ridges. Abundant on the Atlantic coasts of Europe.

4. C. thrissa.—One of the most common West Indian fishes, distinguished by the last dorsal ray being prolonged into a filament. Hyrtl has discovered a small accessory branchial organ in this species.

5. C. alosa.—The “Shad” or “Allice Shad,” with very fine and long gill-rakers, from 60 to 80 on the horizontal part of the outer branchial arch, and with one or more black lateral blotches. Coasts of Europe, ascending rivers.

6. C. finta.—The “Shad” or “Twaite Shad,” with stout osseous gill-rakers, from 21 to 27 on the horizontal part of the outer branchial arch, and spotted like the preceding species. Coasts of Europe, ascending rivers, and found in abundance in the Nile.

7. C. menhaden.—The “Mossbanker,” common on the Atlantic coasts of the United States. The economic value of this fish is surpassed in America only by that of the Gadoids, and derived chiefly from its use as bait for other fishes, and from the oil extracted from it, the annual yield of the latter exceeding that of the whale (from American Fisheries). The refuse of the oil factories supplies a material of much value for artificial manures.

[See G. Brown Goode, “The Natural and Economical History of the American Menhaden,” in U.S. Commission of Fish and Fisheries, Part V., Washington, 1879, 8vo.]

8. C. sapidissima.—The American Shad, abundant, and an important food-fish on the Atlantic coasts of North America. Spawns in fresh water.

9. C. mattowocca.—The “Gaspereau” or “Ale-wife,” common on the Atlantic coasts of North America, ascending into freshwater in early spring, and spawning in ponds and lakes.

10. C. pilchardus.—The “Pilchard” or the “Sardine,” equally abundant in the British Channel, on the coast of Portugal, and in the Mediterranean, and readily recognised by radiating ridges on the operculum, descending towards the sub-operculum.

11. C. sagax.—Representing the Pilchard in the Pacific, and found in equally large shoals on the coasts of California, Chile, New Zealand, and Japan.

12. C. toli.—The subject of a very extensive fishery on the coast of Sumatra for the sake of its roes, which are salted and exported to China, the dried fish themselves being sent into the interior of the island. The fish is called “Trubu” by the Malays, about 18 inches long, and it is said that between fourteen and fifteen millions are caught annually.

13. C. scombrina.—The “Oil-Sardine” of the eastern coast of the Indian Peninsula.

---

Other, but less important genera of Clupeoids with serrated abdomen, are Clupeoides, Pellonula, Clupeichthys, Pellona, Pristigaster, and Chirocentrodon (these three last with very small or without any ventral fins).

Albula.—Body oblong, moderately compressed; abdomen flat. Scales of moderate size, adherent; lateral line distinct. Eyes covered with a broad annular adipose membrane. Snout pointed, the upper jaw projecting beyond the lower. Mouth inferior, of moderate width, with villiform teeth; intermaxillary juxtaposed to the upper anterior edge of the maxillary. Dorsal fin opposite to the ventrals; anal fin shorter than dorsal. Gill-membranes entirely separate, with numerous branchiostegals.

One species only (A. conorhynchus), ranging over all tropical and sub-tropical seas, and very common in many localities near the coasts. It grows to a length of from two to three feet, and is not valued as food.

Elops.—Body rather elongate, moderately compressed; abdomen flat. Scales small, adherent; lateral line distinct. A narrow osseous lamella, attached to the mandibulary symphysis, covers the part between the mandibles. Snout pointed; mouth wide, anterior; intermaxillary short, maxillary forming the lateral part of the mouth. Bands of villiform teeth in the jaws, on the vomer, palatine and pterygoid bones, on the tongue, and on the base of the skull. Dorsal fin opposite to ventrals; anal rather shorter than dorsal. Gill-membranes entirely separate, with very numerous branchiostegals.

Two species, of which one, E. saurus, is, like the preceding fish, spread over all tropical and sub-tropical seas; it exceeds a length of three feet, and is not esteemed as food.

Fig. 301.—Elops saurus.

Megalops.—Body oblong, compressed, abdomen flat. Scales large, adherent; lateral line distinct. A narrow osseous lamella, attached to the mandibulary symphysis, between the mandibles. Snout obtusely conical; mouth anterior, lower jaw prominent; intermaxillary short; maxillary forming the lateral part of the mouth. Bands of villiform teeth in the jaws, on the vomer, palatine and pterygoid bones, on the tongue and on the base of the skull. Dorsal fin opposite to, or immediately behind, the ventrals; anal rather larger than dorsal. Gill-membranes entirely separate, with numerous branchiostegals. Pseudobranchiæ none.

Two species, one belonging to the Indo-Pacific (M. cyprinoides), the other to the Atlantic (M. thrissoides); they are the largest fishes of this family, exceeding a length of five feet, and excellent eating. Young specimens enter freely fresh waters.

Chanos.—Body oblong, compressed; abdomen flat. Scales small, striated, adherent; lateral line distinct. Snout depressed; mouth small, anterior, transverse, the lower jaw with a small symphysial tubercle. Intermaxillary in juxtaposition to the upper anterior edge of maxillary. Teeth none. Dorsal fin opposite to the ventrals; anal small, shorter than dorsal; caudal deeply forked. Gill-membranes entirely united below, and free from the isthmus. Branchiostegals four, long. An accessory branchial organ in a cavity behind the gill-cavity proper. Air-bladder divided by a constriction into an anterior and posterior portion. Mucous membrane of the œsophagus raised in a spiral fold. Intestine with many convolutions.

Two species from the Indo-Pacific, of which Ch. salmoneus is extremely common; it enters fresh waters, and exceeds a length of four feet; its flesh is highly esteemed. The accessory branchial organ and the skeleton have been described by Müller, “Bau und Grenzen der Ganoiden,” p. 75; and by Hyrtl, “Denkschr. Ak. Wiss. Wien.” xxi. 1883, p. 1.

Fig. 302.—Chanos salmoneus.

---

The remaining genera belonging to this family are Spratelloides, Dussumieria, and Etrumeus, which together form a small group, distinguished by an anterior and lateral mouth, by the upper jaw not overlapping the lower, by a rounded abdomen, and by lacking the gular plate of some of the preceding genera.

Twenty-third Family—Bathythrissidæ.

Body oblong, with rounded abdomen, covered with cycloid scales; head naked; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Opercular apparatus complete. Adipose fin none; dorsal fin much elongate, many rayed; anal fin short. Stomach with a blind sac; pyloric appendages numerous. Gill-apparatus well developed; pseudobranchiæ; gill-openings wide; an air-bladder. Ova very small; ovaries without duct.

One genus and species only (Bathythrissa dorsalis) from deep water (350 fathoms) off the coast of Japan. This remarkable fish has the appearance of a Coregonus, and attains to a length of two feet. Nothing is known of its osteology, but possibly a fossil genus from the Gyps of Montmartre; Notæus, which has also a long dorsal fin, may prove to belong to the same family.

Twenty-fourth Family—Chirocentridæ.

Body covered with thin, deciduous scales; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally, both bones being firmly united, in juxtaposition. Opercular apparatus complete. Adipose fin none; the dorsal fin belongs to the caudal portion of the vertebral column. Stomach with a blind sac; intestine short, the mucous membrane forming a spiral fold; pyloric appendages none. Pseudobranchiæ none; air-bladder incompletely divided into cells; gill-opening wide.

One genus and species only (Chirocentrus dorab) is known, which is common in the Indian Ocean, and attains to a length of about three feet; it is not esteemed as food. Remains of fishes similar to Chirocentrus are found in the marl slates of Padang, in Sumatra.

Twenty-fifth Family—Alepocephalidæ.

Body with or without scales; head naked; barbels none. Margin of the upper jaw formed by the intermaxillaries and maxillaries, the former being placed along the upper anterior edge of the latter. Opercular apparatus complete. Adipose fin none; the dorsal fin belongs to the caudal portion of the vertebral column. Stomach curved, without blind sac; pyloric appendages in moderate number. Pseudobranchiæ; air-bladder absent. Gill-openings very wide.

Before the voyage of the “Challenger” one species only of this family was known, Alepocephalus rostratus, a rare fish from the Mediterranean; now, four genera with seven species are known, and there is no doubt that this family is one of the most characteristic, and will prove to be one of the most generally distributed forms, of the deep-sea. Their vertical range varies between 345 (Xenodermichthys) and 2150 (Bathytroctes) fathoms. They approach the Salmonoids, but lack invariably the adipose fin. Their dentition is very feeble; their eye large; bones thin. Coloration black.

Alepocephalus has thin cycloid scales; a mouth of moderate width, and no teeth on the maxillary.

Bathytroctes has cycloid scales, a wide mouth, and teeth on the maxillary as well as intermaxillary.

Platytroctes has small keeled scales and no ventrals.

Xenodermichthys with fine nodules instead of scales.

Twenty-sixth Family—Notopteridæ.

Head and body scaly; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Opercular apparatus incomplete. Tail prolonged, tapering. Adipose fin none. Dorsal short, belonging to the caudal portion of the vertebral column; anal very long. Stomach without blind sac; two pyloric appendages. Pseudobranchiae none; air-bladder present, divided in the interior. The ova fall into the cavity of the abdomen before exclusion. On each side a parieto-mastoid cavity leading into the interior of the skull.

One genus only (Notopterus) with five species which inhabit fresh waters of the East Indies and West Africa. Well-preserved remains of this genus occur in the marl slates of Padang, in Sumatra. Their air-bladder is divided into several compartments, and terminates in two horns anteriorly and posteriorly, the anterior horns being in direct connection with the auditory organ.

Twenty-seventh Family—Halosauridæ.

Body covered with cycloid scales; head scaly; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Opercular apparatus incomplete. Adipose fin none. The short dorsal belongs to the abdominal part of the vertebral column; anal very long. Stomach with a blind sac; intestine short; pyloric appendages in moderate number. Pseudobranchiæ none. Air-bladder large, simple; gill-openings wide. Ovaries closed.

The only genus belonging to this family was discovered by the Madeiran ichthyologist Johnson, in 1863; but since then the naturalists of the “Challenger” expedition have added four other species, showing that this type is a deep-sea form and widely distributed; the specimens were dredged in depths varying from 560 to 2750 fathoms.

Twenty-eighth Family—Hoplopleuridæ.

Body generally with four series of subtriangular scutes, and with intermediate scale-like smaller ones. One (?) dorsal only; head long, with the jaws produced.

Extinct; developed in the chalk and extending into tertiary formations: Dercetis (with the upper jaw longest), Leptotrachelus, Pelargorhynchus, Plinthophorus, Saurorhamphus (with the lower jaw longest), Eurypholis; Ischyrocephalus (?). The latter genus, from cretaceous formations of Westphalia, is said to have two dorsal fins.

Twenty-ninth Family—Gymnotidæ.

Head scaleless; barbels none. Body elongate, eel-shaped. Margin of the upper jaw formed in the middle by the intermaxillaries, and laterally by the maxillaries. Dorsal fin absent or reduced to an adipose strip; caudal generally absent, the tail terminating in a point. Anal fin exceedingly long. Ventrals none. Extremity of the tapering tail capable of being reproduced. Vent situated at, or at a short distance behind, the throat. Humeral arch attached to the skull. Ribs well developed. Gill-openings rather narrow. Air-bladder present, double. Stomach with a cæcal sac and pyloric appendages. Ovaries with oviducts.

Eel-like freshwater fishes from Tropical America.

Sternarchus.—Tail terminating in a distinct small caudal fin. Teeth small. A rudimentary dorsal fin is indicated by an adipose band fitting into a groove on the back of the tail; it is easily detached, so as to appear as a thong-like appendage fixed in front. Branchiostegals four.

Eight species, some have the snout compressed and of moderate length, like St. Bonapartii from the River Amazons; others have it produced into a long tube, as St. oxyrhynchus from the Essequibo.

Rhamphichthys.—Caudal fin none; teeth none; no trace of a dorsal fin. No free orbital margin.

Six species, of which, again, some have a tubiform snout, whilst in the others it is short.

Sternopygus.—Caudal fin none; no trace of a dorsal fin. Both jaws with small villiform teeth; similar teeth on each side of the palate. Body scaly.

Four species, very common, and growing to a length of 30 inches.

Carapus.—Caudal fin none; no trace of a dorsal fin. A series of conical teeth in each jaw. Anterior nostrils, wide in the upper lip. Body scaly.

One species (C. fasciatus) extremely common, and found all over tropical America, east of the Andes, from 18 to 24 inches long.

Gymnotus.—Caudal and dorsal fins absent; anal extending to the end of the tail. Scales none. Teeth conical, in a single series. Eyes exceedingly small.

The “Electric Eel” is the most powerful of electric fishes, growing to a length of six feet, and extremely abundant in certain localities of Brazil and the Guyanas. The electric organ consists of two pairs of longitudinal bodies, situated immediately below the skin, above the muscles; one pair on the back of the tail, and the other pair along the anal fin. Each fasciculus is composed of flat partitions or septa, with transverse divisions between them. The outer edge of the septa appear in nearly parallel lines in the direction of the longitudinal axis of the body, and consist of thin membranes, which are easily torn; they serve the same purpose as the columns in the analogous organ of the Torpedo, making the walls or abutments for the perpendicular and transverse dissepiments, which are exceedingly numerous, and so closely aggregated as to seem almost in contact. The minute prismatic cells, intercepted between these two sorts of plates, contain a gelatinous matter; the septa are about one-thirtieth of an inch from each other, and one inch in length contains a series of 240 cells, giving an enormous surface to the electric organs. The whole apparatus is supplied with more than 200 nerves, which are the continuations of the rami anteriores of the spinal nerves. In their course they give out branches to the muscles of the back, and to the skin of the animal. In the Gymnotus, as in the Torpedo, the nerves supplying the electric organs are much larger than those bestowed on any part for the purposes of sensation or movement.

The graphic description by Humboldt of the capture of Electric Eels by horses driven into the water, which would receive the electric discharges and thus exhaust the fishes, seems to rest either on the imagination of some person who told it to the great traveller or on some isolated incident. Recent travellers have not been able to verify it even in the same parts of the country where the practice was said to exist.

Thirtieth Family—Symbranchidæ.

Body elongate, naked or covered with minute scales; barbels none. Margin of the upper jaw formed by the intermaxillaries only, the well developed maxillaries lying behind and parallel to them. Paired fins none. Vertical fins rudimentary, reduced to more or less distinct cutaneous folds. Vent situated at a, great distance behind the head. Ribs present. Gill-openings confluent into one slit situated on the ventral surface. Air-bladder none. Stomach without cæcal sac or pyloric appendages. Ovaries with oviducts.

The fishes of this family consist of freshwater-fishes from tropical America and Asia, which, however, enter also brackish water; and of a truly marine genus from Australia.

Amphipnous.—Vent in the posterior half of the body, which is covered with minute scales longitudinally arranged.

A common fish (A. cuchia) in Bengal, remarkable for its singular respiratory apparatus. It has only three branchial arches, with rudimentary branchial laminæ, and with very narrow slits between the arches. To supplement this insufficient respiratory apparatus, a lung-like sac is developed on each side of the body behind the head, opening between the hyoid and first branchial arch. The interior of the sac is abundantly provided with blood-vessels, the arterial coming from the branchial arteries, whilst those issuing from it unite to form the aorta. A. cuchia approaches the Eels in having the humeral arch not attached to the skull.

Monopterus.—Vent in the posterior half of the body, which is naked. Three branchial arches with rudimentary gills, but without breathing sac.

One species (M. javanicus), which is extremely common in the East Indian Archipelago and in the eastern parts of the Continent. Upwards of three feet long.

Symbranchus.—Vent in the posterior half of the body, which is naked. Four branchial arches with well developed gills.

Three species, of which one (S. marmoratus) is extremely common in tropical America, and the other (S. bengalensis) not less so in the East Indies.

Chilobranchus.—Vent in the anterior half of the length of the body, which is naked. Vertical fins reduced to a simple cutaneous fold, without rays.

A small fish (Ch. dorsalis) from North Western Australia and Tasmania.

Thirty-First Family—Murænidæ.

Body elongate, cylindrical or “band-shaped, naked or with rudimentary scales. Vent situated at a great distance from the head. Ventral fins none. Vertical fins, if present, confluent, or separated by the projecting tip of the tail. Sides of the upper jaw formed by the tooth-bearing maxillaries, the fore part by the intermaxillary, which is more or less coalescent with the vomer and ethmoid. Humeral arch not attached to the skull. Stomach with a blind sac; no pyloric appendages. Organs of reproduction without efferent ducts.

The “Eels” are spread over almost all fresh waters and seas of the temperate and tropical zones; some descend to the greatest depths of the oceans. The young of some have a limited pelagic existence. (Leptocephali, see p. 179.) At Monte Bolca fossil remains are very numerous, belonging to recent genera, Anguilla, Sphagebranchus, and Ophichthys; even larval Leptocephales have been preserved. Anguilla has been found also in the chalk of Aix and Oeningen.

In the majority of the species the branchial openings in the pharynx are wide slits (Murænidæ platyschistæ); in others, the true Murænæ, (Murænidæ engyschistæ) they are narrow.

Nemichthys.—Exceedingly elongate, band-shaped; tail tapering into a point. Vent approximate to the pectorals, but the abdominal cavity extending far behind the vent. Jaws produced into a long slender bill, the upper part being formed by the vomer and intermaxillaries. The inner surface of the bill covered with small tooth-like asperities. Eye large. The nostrils of each side are close together, in a hollow before the eye. Gill-openings wide, nearly confluent. Pectoral and vertical fins well developed.

This very singular type is a deep-sea form, occurring at depths of from 500 to 2500 fathoms. The two species known have hitherto been found in the Atlantic only.

Cyema.—This genus combines the form of the snout of Nemichthys, with the soft and shorter body of a Leptocephalus; but the gill-openings are very narrow and close together on the abdominal surface. Vent in about the middle of the length of the body; vertical fins well developed, confined to, and surrounding, the tail. Pectoral fins well developed. Eye very small.

Known from two specimens only, 4½ inches long, dredged in depths of 1500 and 1800 fathoms in the Pacific and Antarctic Oceans.

Saccopharynx.—Deep-sea Congers, with the muscular system very feebly developed, with the bones very thin, soft, and wanting in inorganic matter. Head and gape enormous. Snout very short, pointed, flexible, like an appendage overlapping the gape. Maxillary and mandibulary bones very thin, slender, arched, armed with one or two series of long, slender, curved, widely set teeth, their points being directed inwards; palate toothless. Gill-openings wide, at some distance from the head, at the lower part of the sides; gills very narrow, free, and exposed. Trunk of moderate length. Stomach distensible in an extraordinary degree. Vent at the end of the trunk. Tail band-like, exceedingly long, tapering in a very fine filament. Pectoral small, present. Dorsal and anal fins rudimentary.

This is another extraordinary form of Deep-sea Eels; the muscular system, except on the head, is very feebly developed; the bones are as thin, soft, and wanting in inorganic matter, as in the Trachypteridæ. This fish is known from three specimens only, which have been found floating on the surface of the North Atlantic, with their stomachs much distended, having swallowed some other fish, the weight of which many times exceeded that of their destroyer. It attains to the length of several feet.

Synaphobranchus.—Gill-openings ventral, united into a longitudinal slit between the pectoral fins, separate internally. Pectoral and vertical fins well developed. Nostrils lateral, the anterior subtubular, the posterior round, before the lower half of the eye. Cleft of the mouth very wide; teeth small; body scaly. Stomach very distensible.

Deep-sea Congers, with well-developed muscular system, spread over all oceans, and occurring in depths of from 345 to 2000 fathoms. Four species are known. Probably attaining to the same length as the Conger.

Anguilla.—Small scales imbedded in the skin. Upper jaw not projecting beyond the lower. Teeth small, forming bands. Gill-openings narrow, at the base of the pectoral fins. The dorsal fin commences at a considerable distance from the occiput.

Some twenty-five species of “Eels” are known from the freshwaters and coasts of the temperate and tropical zones; none have been found in South America or the west coast of North America and West Africa. The following are the most noteworthy:—The common European species (A. anguilla) is spread over Europe to 64° 30´ lat. N., and all round the Mediterranean area, but is not found either in the Danube or in the Black and Caspian Seas; it extends across the Atlantic to North America. The form of the snout varies much, and some naturalists have believed that specimens with a broad and obtuse snout were specifically distinct from those with pointed snout. However, every degree of breadth of the snout may be observed; and a much safer way of recognizing this species, and distinguishing it from other European Eels, is the forward position of the dorsal fin; the distance between the commencement of the dorsal and anal fins being as long as, or somewhat longer than, the head. Eels grow generally to a length of about three feet, but the capture of much larger examples is on record. Their mode of propagation is still unknown. So much only is certain that they do not spawn in fresh water, that many full-grown individuals, but not all, descend rivers during the winter months, and that some of them at least must spawn in brackish water or in deep water in the sea; for in the course of the summer young individuals from three to five inches long ascend rivers in incredible numbers, overcoming all obstacles, ascending vertical walls or floodgates, entering every larger and smaller tributary, and making their way even over terra firma to waters shut off from all communication with rivers. Such immigrations have been long known by the name of “Eel-fairs.” The majority of the Eels which migrate to the sea appear to return to fresh water, but not in a body, but irregularly, and throughout the warmer part of the year. No naturalist has ever observed these fishes in the act of spawning, or found mature ova; and the organs of reproduction of individuals caught in fresh water are so little developed and so much alike, that the female organ can be distinguished from the male only with the aid of a microscope.

The second species found in Great Britain, on the coasts of Europe generally, in China, New Zealand, and the West Indies, is (A. latirostris) the “Grig” or “Glut,” which prefers the neighbourhood of the sea to distant inland-waters, and in which the dorsal fin begins farther backwards, the distance between the commencement of the dorsal and anal fins being shorter than the head; its snout seems to be always broad. On the American side of the Atlantic other species, beside A. anguilla are found in abundance: A. bostoniensis, A. texana. The largest Eels occur in lakes of the islands of the Indo-Pacific, and they play a conspicuous part in the mythology of the South-Sea Islanders and Maories; individuals of from eight to ten feet in length have been seen, and referred to several species, as A. mauritiana, fidjiensis, obscura, aneitensis, etc.

Conger.—Scaleless. Cleft of the mouth wide, extending at least to below the middle of the eye. Maxillary and mandibulary teeth arranged in series, one of which contains teeth of equal size, and so closely set as to form a cutting edge. No canine teeth. Vomerine band of teeth short. Pectoral and vertical fins well developed, the dorsal commencing behind the root of the pectoral. Gill-openings large, approximate to the abdomen. The posterior nostril opposite to the upper or middle part of the orbit, the anterior in a tube. Eyes well developed.

The “Congers” are marine Eels; the best known species (C. conger) seems to be almost cosmopolitan, and is plentiful all round Europe, at St. Helena, in Japan, and Tasmania. It attains to a length of eight feet, and thrives and grows rapidly even in confinement, which is not the case with the freshwater Eel. Three other species are known, of which C. marginatus from the Indian Ocean, is the most common. Leptocephalus morrisii is an abnormal larval condition of the Conger.

Genera allied to Conger are Poeciloconger, Congromurcæna, Uroconger, and Heteroconger.

Murænesox.—Scaleless. Snout produced. Jaws with several series of small closely set teeth, anteriorly with canines; vomer with several long series of teeth, the middle of which is formed by large conical or compressed teeth. Gill-openings wide, approximate to the abdomen. Pectoral and vertical fins well developed, the dorsal beginning above the gill-opening. Two pairs of nostrils, the posterior opposite to the upper part or middle of the eye.

Four species from tropical seas, M. cinereus being very common in the Indian Ocean, and attaining to a length of six feet.

Nettastoma.—Scaleless. Snout much produced, depressed. Jaws and vomer with bands of card-like teeth, those along the median line of the vomer being somewhat the larger. Vertical fins well developed; pectorals none. Gill-openings of moderate width, open. Nostrils on the upper surface of the head, valvular; the anterior near to the end of the snout, the posterior above the anterior angle of the eye.

This genus lives at some depth, the Japanese species (N. parviceps) having been obtained at 345 fathoms. N. melanurum from the Mediterranean, seems to inhabit a similar depth. Hyoprorus is its Leptocephalid form.

Genera allied to Murcænesox are Saurenchelys, Oxyconger, Hoplunnis, and Neoconger; in all these the nostrils have a superior or lateral position. In other genera the nostrils perforate the upper lip, as in Myrus, Myrophis, Paramyrus, Chilorhinus, Murænichthys, and Ophichthys, the last genus deserving of particular mention on account of its great range and common occurrence.

Ophichthys.—Nostrils labial; extremity of the tail free, not surrounded by a fin.

More than eighty species are known, many of which are abundant on the coasts of the tropical and sub-tropical zones. They do not attain to a large size, but many must be extremely voracious and destructive to other fishes, if we draw an inference from the formidable dentition with which their jaws and palate is armed. Other species have much more feeble, and some even obtuse teeth, better adapted for seizing Crustaceans than vigorous and slippery fishes. Some have rudimentary pectoral fins or lack them altogether. Many are highly ornamented with bands or spots, the coloration being apparently very constant in the several species.

Fig. 303.—Ophichthys crocodilinus, from the Indo-Pacific.

Moringua.—Body scaleless, cylindrical, with the trunk much longer than the tail. Pectorals none or small; vertical fins but little developed, limited to the tail. Posterior nostrils in front of the small eye. Cleft of the mouth narrow; teeth uniserial. Heart placed far behind the branchiæ. Gill-openings rather narrow, inferior.

Six species from freshwaters, brackish water, and the coasts of India to the Fiji Islands.

Muræna.—Scaleless. Teeth well developed. Gill-openings and clefts between the branchial arches narrow. Pectoral fins none; dorsal and anal fins well developed. Two nostrils on each side of the upper surface of the snout; the posterior a narrow round foramen, with or without tube; the anterior in a tube.

Fig. 304.—Head of a Muræna.

Fig. 305.—Muræna pavonina, from Southern Seas.

The Murænas are as abundantly represented in the tropical and sub-tropical zones, and have nearly the same range, as Ophichthys. The number of species known exceeds eighty. The majority are armed with formidable pointed teeth, well suited for seizing other fish on which they prey. Large specimens thus armed readily attack persons in and out of the water; and as some species attain a length of some six or eight feet, they are justly feared by fishermen. The minority of species have obtuse and molar-like teeth, their food consisting chiefly of Crustaceans and other hard-shelled animals. Most of the Murænas are beautifully coloured and spotted, some in a regular and constant manner, whilst in others the pattern varies in a most irregular fashion: they have quite the appearance of snakes. The Muræna of the Ancient Romans is Muræna helena, which is not confined to the Mediterranean, but also found in the Indian Ocean and on the coast of Australia. Its skin is of a rich brown, beautifully marked with large yellowish spots, each of which contains smaller brown spots.

Fig. 306.—Muræna picta, from the Indo-Pacific.

Gymnomuræna differs from Muræna in having the fins reduced to a short rudiment near the end of the tail. Six species are known growing to a length of eight feet.

Fig. 307.—Gymnomuræna vittata, from Cuba.

Myroconger and Enchelycore belong to the same sub-family as Muræna, but the former is provided with pectoral fins, and in the latter the posterior nostril is a long slit, and not round as in the other genera.

FIFTH ORDER—LOPHOBRANCHII.

The gills are not laminated, but composed of small rounded lobes attached to the branchial arches. Gill-cover reduced to a large simple plate. Air-bladder simple, without pneumatic duct. A dermal skeleton composed of numerous pieces arranged in segments, replaces more or less soft integuments. Muscular system not much developed. Snout prolonged. Mouth terminal, small, toothless, formed as in Acanthopterygians.

Fig. 308.—Gills of Hippocampus abdominalis.

First Family—Solenostomidæ.

Gill-openings wide. Two dorsal fins, the rays of the anterior not articulated. All the other fins well developed.

One living genus only is known, which was preceded in the tertiary epoch by Solenorhynchus (Monte Postale).

Solenostoma.—Snout produced into a long tube. Body compressed, with very short tail. All parts covered with thin skin, below which there is a dermal skeleton formed by large star-like ossifications. The soft dorsal and anal fins on elevated bases; caudal fin long. Ventral fins inserted opposite to the anterior dorsal, close together, seven-rayed; they are free in the male, but in the female their inner side coalesces with the integuments of the body, a large pouch for the reception of the eggs being formed thereby. Air-bladder and pseudobranchiæ absent. Branchiostegals four, very thin. Intestinal tract very simple, with a stomachic dilatation, without pyloric appendages. Ova very small.

The dermal skeleton of this singular type is formed by star-like ossifications, four in each horizontal and vertical series on the side of the fore part of the trunk; each consists of four or three radiating branches by which it joins the neighbouring bones; on the hind part of the trunk and tail the series are diminished to two. The dorsal and abdominal profiles in front of the fins are protected by similar bones. The vertebral column is composed of eighteen abdominal and fifteen caudal vertebræ, the vertebræ gradually decreasing in length backwards, so that the shortness of the tail is caused not only by the smaller number of vertebræ, but also by their much lesser length. Neural and hæmal spines are developed. The pelvis consists of two pairs of cartilaginous laminæ, the convex margin of the anterior fitting into an angle of a dermal bone which separates the pelvis from the well-ossified humeral arch.

The singular provision for the retention and protection of the eggs has been described above (p. 162, figs. 73 and 74), and we have only to repeat here that it is the female which takes care of the progeny, and not the male as in the following family. Two or three small species are known from the Indian Ocean; they are beautifully marked, especially the male, which also appears to be of smaller size in this genus than the female.

Second Family—Syngnathidæ.

Gill-openings reduced to a very small opening near the upper posterior angle of the gill-cover. One soft dorsal fin; no ventrals, and, sometimes, one or more of the other fins are also absent.

Small marine fishes, which are abundant on such parts of the coasts of the tropical and temperate zones as offer by their vegetation shelter to these defenceless creatures. They are bad swimmers (the dorsal fin being the principal organ of locomotion), and frequently and resistlessly carried by currents into the open ocean or to distant coasts. All enter brackish water, some fresh water. The strata of Monte Bolca and Licata (Sicily) have, yielded evidence of their existence in the tertiary epochs; beside species of Siphonostoma and Syngnathus (Pseudosyngnathus), remains of an extinct genus, Calamostoma, allied to Hippocampus, but with a distinct caudal fin, have been found. On their propagation see p. 163, Fig. [76].

A. Syngnathina.—The tail is not prehensile, and generally provided with a caudal fin.—Pipe-Fishes.

Siphonostoma.—Body with distinct ridges, the upper caudal ridge continuous with the lateral line, but not with the dorsal ridge of the trunk. Pectoral and caudal fins well developed; dorsal fin of moderate length, opposite to the vent. Humeral bones movable, not united into a “breast-ring.” Males with an egg-pouch on the tail, the eggs being covered by cutaneous folds.

Two species, of which S. typhle is common on the British, and generally distributed on the European coasts.

Syngnathus.—Body with the ridges more or less distinct, the dorsal ridge of the trunk not being continuous with that of the tail. Pectoral fins well developed; caudal present. Dorsal fin opposite or near to the vent. Humeral bones firmly united into the breast-ring. Egg-pouch as in Siphonostoma.

The distribution of this genus nearly coincides with that of the family, some fifty species being known. S. acus, the great Pipe-fish (see Fig. [75], p. 163), is one of the most common European fishes, extending across the Atlantic and southwards to the Cape of Good Hope; it attains a length of 18 inches. Another very common species, frequently met at sea, and spread over nearly all the tropical and sub-tropical seas, is S. pelagicus, agreeably marked with alternate brown and silvery cross-bars.

Doryichthys.—Body with the ridges well developed. Pectoral and caudal fins present. Dorsal fin long or of moderate length, opposite to the vent. Humeral bones firmly united. Males with the lower ridges of the abdomen dilated, the dilated parts forming a broad groove for the reception of the ova.

In these Pipe-fishes the ova are not received in a completely closed pouch, but glued on to the surface of the abdomen. Twenty species from tropical seas.

Nerophis.—Body smooth, rounded, with scarcely any of the ridges distinct. Pectoral fin none, caudal absent or rudimentary, the tail tapering into a point. Dorsal fin of moderate length, opposite to the vent. The ova are attached to the soft integument of the abdomen of the male, and are not covered by lateral folds of the skin.

Seven species from the European seas and the Atlantic. N. æquoreus (Ocean Pipe-fish), N. ophidion (Straight-nosed Pipe-fish), and N. lumbriciformis (Little Pipe-fish), are common on the British coasts.

Protocampus.—The whole dermal skeleton is covered with skin. A broad cutaneous fold runs along the back in front and behind the dorsal; a similar fold along the abdomen. Pectoral fin none; caudal very small.

The single species of this remarkable genus, P. hymenolomus, occurs in the Falkland Islands. It may be regarded as an embryonal form of Nerophis, the median skin-folds being evidently remains of the fringe which surrounds the body of the embryo.

The other genera belonging to this group are, Icthyocampus, Nannocampus, Urocampus, Leptoichthys, Coelonotus, and Stigmatophora.

Hippocampina.—The tail is prehensile, and invariably without caudal fin.—Sea-horses.

Gastrotokeus.—Body depressed, the lateral line running along the margin of the abdomen. Shields smooth. Tail shorter than the body. Pectoral fins. No pouch is developed for the ova, which are imbedded in the soft integument of the abdomen of the male.

Gastrotokeus biaculeatus, very common in the Indian Ocean to the coasts of Australia.

Solenognathus.—Body compressed, deeper than broad. Shields hard, rugose, with round or oval interannular plates; and without elongate processes. Tail shorter than the body. Pectoral fins.

Three species, from the Chinese and Australian Seas; they are the largest of Lophobranchs, S. hardwickii, attaining to a length of nearly two feet.

Fig. 309.—Phyllopteryx eques.

Phyllopteryx.—Body compressed, or as broad as deep. Shields smooth, but some or all of them are provided with prominent spines or processes on the edges of the body; some of the processes with cutaneous filaments. A pair of spines on the upper side of the snout and above the orbit. Tail about as long as the body. Pectoral fins. The ova are imbedded in soft membrane on the lower side of the tail, without a pouch being developed.

Three species from the coasts of Australia. The protective resemblances with which many Lophobranchs are furnished, attain to the highest degree of development in the fishes of this genus. Not only their colour closely assimilates that of the particular kind of seaweed which they frequent, but the appendages of their spines seem to be merely part of the fucus to which they are attached. They attain a length of 12 inches.

Hippocampus.—Trunk compressed, more or less elevated. Shields with more or less prominent tubercles or spines. Occiput compressed into a crest, terminating at its supero-posterior corner in a prominent knob (coronet). Pectoral fins. The males carry the eggs in a sac at the base of the tail, opening near the vent.

A singular resemblance of the head and fore part of the body to that of a horse, has given to these fishes the name of “Sea-horses.” They are abundant between and near the tropics, becoming scarcer in higher latitudes. Some twenty species are known, some of which have a wide geographical range, as they are often carried to great distances with floating objects to which they happen to be attached.—Acentronura is a genus closely allied to Hippocampus.

SIXTH ORDER—PLECTOGNATHI.

Teleosteous fishes with rough scales, or with ossifications of the cutis in the form of scutes or spines; skin sometimes entirely naked. Skeleton incompletely ossified, with the vertebræ in small number. Gills pectinate; a narrow gill-opening in front of the pectoral fins. Mouth narrow; the bones of the upper jaw generally firmly united. A soft dorsal fin, belonging to the caudal portion of the vertebral column, opposite to the anal; sometimes elements of a spinous dorsal besides. Ventral fin none, or reduced to spines. Air-bladder without pneumatic duct.

First Family—Sclerodermi.

Snout somewhat produced; jaws armed with distinct teeth in small number. Skin with scutes or rough. The elements of a spinous dorsal and ventral fins generally present.

Marine fishes of moderate or small size, very common in the tropical zone, but scarcer in higher latitudes. They have been found in three localities of tertiary strata, viz., at Monte Bolca, where a species of Ostracion occurs, and in the Schists of Glaris, from which two genera have been described, Acanthoderma and Acanthopleurus, closely allied to Balistes and Triacanthus. Glyptocephalus from the Isle of Sheppey has the skull of a Balistes, but its body is covered with tubercles arranged in regular series. The Scleroderms may be divided into three very natural groups:—

A. Triacanthina.—The skin is covered with small, rough, scale-like scutes. A spinous dorsal fin with from four to six spines. A pair of strong, movable ventral spines, joined to the pelvic bone.

To this group belong the genera Triacanthodes, Hollardia, and Triacanthus, represented by five species, of which Triacanthus brevirostris from the Indian Ocean is the most common.

B. Balistina.—Body compressed, covered with movable scutes or rough. Spinous dorsal reduced to one, two, or three spines. Ventral fins reduced to a single pelvic prominence, or entirely absent.

To this group belong the genera Balistes, Monacanthus, and Anacanthus, the last genus being distinguished by a barbel at the lower jaw.

Fig. 310.—Balistes vidua.

Balistes, or the “File-fishes” proper, inhabit the tropical and sub-tropical seas; shoals of young are not rarely met with in mid-ocean. Some thirty species are known, many attaining a length exceeding two feet; but the majority are much smaller, and frequently beautifully and symmetrically marked. Both jaws are armed with eight strong incisor-like and obliquely truncated teeth, by which these fishes are enabled to break off pieces of corals on which they feed, or to chisel a hole into the hard shell of Mollusca, in order to extract the soft parts. They destroy an immense number of Mollusks, thus becoming most injurious to the pearl-fisheries. The first of their three dorsal spines is very strong, roughened in front like a file, and hollowed out behind to receive the second much smaller spine, which, besides, has a projection in front, at its base, fitting into a notch of the first. Thus these two spines can only be raised or depressed simultaneously, and the first cannot be forced down, unless the second has been previously depressed. The latter has been compared to a trigger, hence a second name, “Trigger-fish,” has been given to these fishes. Some species are armed with a series of short spines or tubercles on each side of the tail. Two species (B. maculatus and B. capriscus), common in the Atlantic, sometimes wander to the British coasts.

The Monacanthus are similarly distributed as the Balistes, and still more abundant, some fifty species being known. Their dentition is very similar, but they possess one dorsal spine only, and their rough scales are so small as to give a velvety appearance to the skin (Figs. [17] and [18], p. 48). Adult males of some of the species possess a peculiar armature on each side of the tail, which in females is much less developed or entirely absent. This armature may consist either in simple spines arranged in rows, or in the development of the minute spines of the scales into long stiff bristles, so that the patch on each side of the tail looks like a brush.

C. Ostraciontina.—The integuments of the body form a hard continuous carapace, consisting of hexagonal scutes juxtaposed in mosaic-fashion. A spinous dorsal and ventral fins are absent; but sometimes indicated by protuberances.

The “Coffer-fishes” (Ostracion) are too well known to require a lengthened description. Only the snout, the bases of the fins, and the hind part of the tail are covered with soft skin, so as to admit of free action of the muscles moving these parts. The mouth is small, the maxillary and intermaxillary bones coalescent, each jaw being armed with a single series of small slender teeth. The short dorsal fin is opposite to the equally short anal. The vertebral column consists of fourteen vertebræ only, of which the five last are extremely short, the anterior elongate. Ribs none. The carapaces of some species are three-ridged, of others four- and five-ridged, of some provided with long spines. Twenty-two species from tropical and sub-tropical seas are known.

Second Family—Gymnodontes.

Body more or less shortened. The bones of the upper and lower jaw are confluent, forming a beak with a trenchant edge, without teeth, with or without median suture. A soft dorsal, caudal and anal are developed, approximate. No spinous dorsal. Pectoral fins; no ventrals.

Marine fishes of moderate or small size from tropical and sub-tropical seas. A few species live in fresh water. Fossil remains of Diodon are not scarce at Monte Bolca and Licata; a distinct genus, Enneodon, has been described from Monte Postale. The Gymnodonts may be divided into three groups:

A. Triodontina.—Tail rather long, with a separate caudal fin. Abdomen dilatable into a very large, compressed, pendent sac, the lower part of which is merely a flap of skin, into which the air does not penetrate, the sac being capable of being expanded by the very long pelvic bone. The upper jaw divided by a median suture, the lower simple.

A single genus and species (Triodon bursarius) from the Indian Ocean.

B. Tetrodontina.—Tail and caudal fin distinct. Part of the œsophagus much distensible, and capable of being filled with air. No pelvic bone.

“Globe-fishes” have a short, thick, cylindrical body, with well developed fins. It is covered with thick scaleless skin, in which, however, spines are imbedded of various sizes. The spines are very small, and but partially distributed over the body in some species, whilst in others they are very large, and occupy equally every part of the body. These fishes have the power of inflating their body by filling their distensible œsophagus with air, and thus assume a more or less globular form. The skin is, then, stretched to its utmost extent, and the spines protrude and form a more or less formidable defensive armour, as in a hedgehog; therefore they are frequently called “Sea-hedgehogs.” A fish thus blown out turns over and floats belly upwards, driving before the wind and waves. However, it is probable that the spines are a protection not only when the fish is on the surface and able to take in air, but also when it is under water. Some Diodonts, at any rate, are able to erect the spines about the head by means of cutaneous muscles; and, perhaps, all fill their stomach with water instead of air, for the same purpose and with the same effect. In some Diodonts the spines are fixed, erect, not movable. The Gymnodonts generally, when taken, produce a sound, doubtless by the expulsion of air from the œsophagus. Their vertebral column consists of a small number of vertebræ, from 20 to 29, and their spinal chord is extremely short. All these fishes have a bad reputation, and they are never eaten; indeed, some of them are highly poisonous, and have caused long continued illness and death. Singularly, the poisonous properties of these fishes vary much as regards intensity, only certain individuals of a species, or individuals from a certain locality, or caught at a certain time of the year, being dangerous. Therefore it is probable that they acquire their poisonous quality from their food, which consists in corals and hard-shelled Mollusks and Crustaceans. Their sharp beaks, with broad masticating posterior surface, are admirably adapted for breaking off branchlets of coral-stocks, and for crushing hard substances.

Fig. 311.—Jaws of Tetrodon.

Fig. 312.—Tetrodon margaritatus.

Tetrodon (including Xenopterus).—Both the upper and lower jaws are divided into two by a mesial suture.

Extremely numerous in tropical and sub-tropical zones, more than sixty species being known. In some of the species the dermal spines are extremely small, and may be absent altogether. Many are highly ornamented with spots or bands. A few species live in large rivers—thus T. psittacus from Brazil; T. fahaka, a fish well known to travellers on the Nile, and likewise abundant in West African rivers; T. fluviatilis from brackish water and rivers of the East Indies. The species figured is one of the smallest, about six inches long, and common in the Indo-Pacific.

Diodon.—Jaws without mesial suture, so that there is only one undivided dental plate above and one below.

In these fishes, as well as in some closely allied genera, the dermal spines are much more developed than in the Tetrodonts; in some the spines are erectile, as in Diodon, Atopomycterus, Trichodiodon, and Trichocyclus; in others they are stiff and immovable, as in Chilomycterus and Dicotylichthys. Seventeen species are known, of which Diodon hystrix is the most common as it is the largest, growing to a length of two feet. It is spread over the Tropical Atlantic as well as Indo-Pacific, as is also a smaller, but almost equally common species, Diodon maculatus.

Fig. 313.—Diodon maculatus.

Fig. 314.—Diodon maculatus, inflated.

C. Molina.—Body compressed, very short; tail extremely short, truncate. Vertical fins confluent. No pelvic bone.

The “Sun-fishes” (Orthagoriscus) are pelagic fishes, found in every part of the oceans within the tropical and temperate zones. The singular shape of their body and the remarkable changes which they undergo with age, have been noticed above (p. 175, Figs. [93], [94]). Their jaws are undivided in the middle, comparatively feeble, but well adapted for masticating their food, which consists of small pelagic Crustaceans. Two species are known. The common Sun-fish, O. mola, which attains to a very large size, measuring seven or eight feet, and weighing as many hundredweights. It has a rough, minutely granulated skin. It frequently approaches the southern coasts of England and the coasts of Ireland, and is seen basking in calm weather on the surface. The second species, O. truncatus, is distinguished by its smooth, tessellated skin, and one of the scarcest fishes in collections. The shortness of the vertebral column of the Sun-fishes, in which the number of caudal vertebra is reduced to seven, the total number being seventeen, and the still more reduced length of the spinal chord have been noticed above (p. 96).