A.—Teleostei.—Acanthopterygii.
1.—Triglidæ.
The fishes of this family are all repulsively ugly. They have an elongate and but slightly compressed body, covered with ctenoid scales, and a large head in which the suborbital bones, which are broad, unite with the præopercular so as to form an osseous plate in the malar region. The pectoral fins are large, and provided with a few detached rays, which perform the function of tactile organs; the ventral fins are situate on the breast. These fishes are extremely voracious.
The most interesting type is the Synanceia termed by the Creoles of Réunion Crapaud de mer, and by those of Mauritius Laffe. In Java it is called Ikan-Satan (Devil-fish), and in Tahiti Nohu. It is distributed throughout almost all the warmer regions of the Indian and Pacific Oceans, and is found in Cochin-China and New Caledonia.
It is never taken in the open sea, but only among the fringing reefs, where it lives constantly concealed in holes or buried in the sand. It does not come out except to make a sudden dart at prey passing within its reach. When irritated it does not eject venom; for the latter to be expelled one has either to press hard upon the poison-sacs, after pushing back with the fingers the membranes covering the dorsal defensive armature, or the naked foot must be placed on the back of the fish. The wound is very painful, and is accompanied by a series of alarming symptoms, which sometimes terminate fatally: fishermen are consequently much afraid of it.
There are a large number of species of this fish, peculiar to different regions. Synanceia brachio ([fig. 101]), the largest specimens of which attain the length of 45 cm., is the most common form in the Tropical Pacific.
Fig. 101.—Synanceia brachio, var. verrucosa. (After Savtschenko.)
The spiny rays of the dorsal fin of Synanceia are sharp-pointed, stout in the middle, and provided on each side with a small canal hollowed out in the thickness of the spine. Towards the middle of the latter there is attached a little double sac, or kind of closed pouch, which, on being compressed, allows the venom to escape in a thin jet which flows into the grooves of the spine. The expulsion of the venom is therefore not a voluntary act on the part of the fish; in order that it shall take place, pressure must be applied to the sacs in which it is contained.
This venom, when extracted from the glands, is limpid, bluish, and slightly acid. When introduced into the tissues, it produces very acute local pain, which extends throughout the affected limb. The pain is excruciating, and sufferers have been observed to become actually delirious, striking and biting those around them, throwing themselves from side to side, and beseeching that the limb should be cut off; some of them have amputated the injured part themselves.
This condition is accompanied by considerable anxiety, and by attacks of leipothymia and sometimes of syncope. In some cases syncope has been followed by death; in others serious phlegmons, complicated by septicæmia, supervene. The inoculated spot becomes bluish, and then sphacelates over a larger or smaller area. These gangrenous wounds heal very slowly, more especially since they are usually produced on the sole of the foot (Bottard).
A single drop of the venom is sufficient to kill frogs in about three hours.
Fig. 102.—Cottus scorpius (Sea Scorpion). (After Savtschenko.)
The genus Cottus, which also belongs to the family Triglidæ, includes some forty venomous species found in the seas of the northern hemisphere, in Europe, Asia, and America.
In France the species of Cottus are generally called chabots (bullheads or miller’s thumbs), chaboisseaux (sea-scorpions), or caramassons. They are abundant on the coast of Normandy, and some of them (river bullheads) live in fresh water; they do not exceed 25 cm. in length. They have a liking for holes in rocks, and fishermen are afraid of being stung by them ([fig. 102]).
Their poison-apparatus resembles that of the Weevers, but is less developed. It is situated in the culs-de-sac formed by the opercular spines. The culs-de-sac are lined with cells which produce a toxic secretion only during the spawning season, from November to the end of January. This fact explains how it is that the species of Cottus are declared by certain fishermen to be very venomous, while others say that they are absolutely harmless.
The genera Scorpæna, Pterois and Pelor also belong to the same group.
Fig. 103.—Scorpæna grandicornis (Caribbean Sea). (After Savtschenko.)
In Scorpæna the body is clothed with scales, and the head is large, slightly compressed, armed with spines, and has a bare pit behind; the single dorsal fin is provided with eleven spiny rays, and there are seven branchiostegal rays. Scorpæna grandicornis ([fig. 103]), found in the Caribbean Sea, is from 30 to 50 cm. in length, and has the back red and the eyes and belly yellow; Scorpæna diabolus ([fig. 104]), which occurs in the Indian Ocean and Tropical Pacific, is red and brown, obliquely striped with white and brown; a third species, Scorpæna porcus (Scorpène truie), of smaller size, is met with in the Mediterranean. The venom of the latter has been studied by A. Briot,[143] who sectioned the dorsal and opercular spines, and macerated them either in physiological saline solution, or in glycerine; he then tested the toxicity of these macerations on certain animals—frogs, rabbits, and rats.
Fig. 104.—Scorpæna diabolus (Indian and Pacific Oceans). (After Savtschenko.)
The frogs alone exhibited, as the result of subcutaneous injection into a limb, slight transient paralysis. No effect was found to be produced by the venom when injected intravenously into the rabbit, or subcutaneously into the rat.
The poison-apparatus of Scorpæna is situated in the spiny rays of the dorsal and anal fins. These rays are enveloped in the inter-radial membrane, which forms a sheath for them, and are scored with a double cannelure. At the bottom of these grooves are the secreting cells, which are elongate, pressed one against the other, and supported at the base by a highly vascular substratum of connective tissue. The venom flows out between the layer of cells and the ensheathing membrane, which is capable of being pushed slightly back as the result of the penetration of the spine into the tissues, and then exerts pressure upon the reservoir. The latter is formed by the distension of the sheath under the pressure of the secreted liquid.
Fig. 105.—Pterois artemata (East Coast of Africa, Indian and Tropical Pacific Oceans). (After Savtschenko.)
There are twelve pairs of dorsal and three pairs of anal glands. The pairs attached to the second anal spine are, as the direct result of the size of the latter, more developed than those of the other spines.
In the Rascasse, the opercular spines of which are greatly developed, there is a rudiment of a poison-apparatus at the bottom of the sheath formed by the skin of the gills.
The species of Pterois ([fig. 105]) are distinguished from those of Scorpæna by their dorsal fins, the rays of which are very long and curved backwards, above the membrane by which they are united. They are found in the Indian and Equatorial Pacific Oceans, and are very beautiful in colour, varying from reddish-brown to bright rose.
The poison-apparatus of these fishes is situated in the dorsal fin, and is precisely similar to that of Scorpæna.
Fig. 106.—Pelor filamentosum (Family Triglidæ, Mauritius).
The species of Pelor ([fig. 106]) present greater resemblance to those of Synanceia, owing to their heads being crushed in in front. Their eyes stand up above the head and are very close together, which helps to give them an extremely ugly appearance. The skin is soft and spongy, and bristles with jagged fleshy shreds.
Their poison-apparatus is placed in the dorsal fins, as in the case of Scorpæna and Pterois.
2.—Trachinidæ.
Genus Trachinus (Weevers).—Four species of Weevers are found in European seas: the Greater Weever (Trachinus draco), the Lesser Weever (T. vipera), the Striped-headed Weever (T. radiatus), and the Mediterranean Spider Weever (T. araneus); other species are met with on the coast of Chile.
Weevers possess two sets of poison-apparatus, one of which is situated on the operculum, the other at the base of the spines of the dorsal fin ([fig. 107]).
Fig. 107.—Trachinus vipera (Lesser Weever).
The spine surmounting the operculum exhibits a double cannelure connected with a conical cavity excavated in the thickness of the base of the opercular bone. This spine is covered with a sheath, beneath which lie the secreting cells. The gland is an offshoot from the skin, and appears as a simple follicle invaginated in the opercular bone ([fig. 108]).
The dorsal apparatus is composed of from five to seven spines, to which the inter-radial membrane forms an adherent sheath which extends almost to the end of the rays. Each spine exhibits a deep double cannelure. The venom flows between the layer of cells clothing the cannelures and the skin, which is distended to allow it to pass.
Towards the base of the spine, the edges of the cannelure are united, and form a hollow, bony cone, the walls of which are lined with the cells that secrete the toxic fluid.
Fig. 108.—A, Operculum and opercular spine of the Lesser Weever (Trachinus vipera); ar, articular surface of the operculum; c. op, body of the opercular spine; c. an, canal of the spine; z, space occupied by the poison-gland. B, Spine belonging to the first dorsal fin; c. an, efferent poison-canal in the spine.
Greater Weevers are usually from 12 to 30 cm. in length, and of a reddish or yellowish-grey colour, with blue or violet spots. They are caught in trawls and are fairly common on sandy bottoms. In the month of June they approach the shore for the purpose of spawning.
The venom of the Weever has formed the subject of interesting studies by Günther, Gressin,[144] Bottard, Phisalix,[145] and more recently by Kobert[146] and A. Briot.[147]
In order to procure sufficient quantities of it for experimental purposes, Briot cuts off the venomous spines and the surrounding tissue with a pair of scissors; he then pounds the whole in a mortar, and mixes the pulp with pure glycerine. After filtration through paper, a toxic solution is obtained, which does not deteriorate by keeping, and is neutral to litmus.
A few drops of this liquid are sufficient to kill guinea-pigs, which, immediately after receiving an injection in the thigh, exhibit paralysis of the leg with tetanic convulsions; twenty-four hours later an eschar is formed, and death supervenes on the second or third day.
Two or three drops, introduced into the marginal vein of the ear of a rabbit, cause death from asphyxia in from four to ten minutes. The heart continues to beat for a fairly long time after respiration has entirely ceased; the blood is not coagulated.
The toxicity of this venom is completely destroyed by heating it to 100° C., by chloride of lime, and by chloride of gold. Antivenomous serum prepared from horses vaccinated against cobra-venom has absolutely no effect upon it in vitro. There is therefore no affinity between this venom and that of snakes.
Weever-venom dissolves the red corpuscles of the horse in the presence of normal heated horse-serum, but does not dissolve them in the presence of fresh serum. The non-heated serum, therefore, as I have shown with reference to the action of cobra-venom on the blood, contains a natural antihæmolysin.
Briot succeeded in vaccinating rabbits by accustoming them to the venom, and in obtaining from them a serum capable of neutralising the latter in vitro, and of immunising fresh rabbits against doses several times lethal, even when injected intravenously.
According to Gressin, the following phenomena are produced in man as the result of Weever-stings:—
“At first there is felt an excruciating, shooting, paralysing pain, which, in the case of nervous persons, may cause attacks of leipothymia ending in syncope. A kind of painful formication next pervades the injured limb, which becomes swollen and inflamed, and may even, if treatment be neglected, form the starting point of a gangrenous phlegmon.
“This condition is frequently accompanied by certain general phenomena—such as fever, delirium, and bilious vomiting, the duration of which is variable, since they may only last for two or three hours, or may continue for several days. Fishermen rightly consider this variability to depend upon the amount of venom that has penetrated into the wound, and especially upon the season at which the accident takes place. The most serious results are recorded during the spawning season, and fishermen regard the Lesser Weever as being the more poisonous.”
3.—Gobiidæ.
In the fishes belonging to this family the body is elongated and depressed, while the spines in the anterior dorsal fin and in the ventral fins are slender, flexible, and seldom very solid. The ventral fins are inserted on the breast or on the throat, and are either separated or united together in the shape of a funnel. The skin is naked or covered with large scales, and the mouth is furnished with teeth. The males are distinguished by the presence of a long genital papilla. These fishes are carnivorous.
Fig. 109.—Callionymus lyra (Dragonet or Skulpin. Family Gobiidæ).
Several species of venomous Gobiidæ are met with on the shores of France and in the tropical zone. The most important of these belong to the genus Callionymus (C. belennus, C. lacertus, C. vulsus, and C. lyra—[fig. 109]).
The Dragonet or Skulpin (Callionymus lyra), which is common on the coast of Calvados, may attain the length of 30 cm. In France it is popularly known as the Doucet, Dragonnet, Lavandière, Cornaud, or Capouri. Its colours are very vivid, orange and deep lilac.
In this fish the præopercular bone ends in three strong, conical, and very sharp points, diverging like the prongs of a trident. The upper margin of the opercular bone bears another point, which is directed upwards.
The skin of the gills forms a common sheath for this defensive armature, and the base of the sheath is prolonged into two culs-de-sac, the surface of which is clothed, during the spawning season, with cylindrical cells, the secretion of which is poisonous.
This venom, which is small in amount, does not appear to have any marked effect upon man (Bottard).
4.—Teuthididæ.
This family of Acanthopterygii includes several species of brilliantly coloured fishes with elongated and laterally compressed bodies, provided with a long dorsal fin, and having, on each side of the tail, a sharp spine placed in front of the anal fin. They are herbivorous, and are confined to the tropical seas.
The principal genera are: Teuthis (India), Acanthurus (Tropical Atlantic), Prionurus (Japan), and Naseus (Red Sea and Indian Ocean). The fishermen of Réunion are much afraid of the wounds inflicted by Acanthurus luridus, which they call Marguerite Porc or Grande Marguerite. A sting from this fish causes a very acute smarting pain, which may last for several hours, but usually has no serious consequences.
The poison-apparatus of these fishes is situated in the dorsal and anal fins, as in Scorpæna.
5.—Batrachiidæ.
The venomous species belonging to this family are few in number. They are found in all tropical seas, but have no representatives in Europe. The best-known species are Batrachus tau (shores of Central America), and B. grunniens, or Grunting Batrachus ([fig. 110]).
Fig. 110.—Batrachus grunniens (West Indies).
Fig. 111.—Thalassophryne reticulata (Panama; Tropical Pacific). (After Savtschenko.)
The Grunting Batrachus, which does not exceed 30 cm. in length, is especially common in West Indian waters. When taken from the water it makes a peculiar grunting sound, whence its name is derived. The pectoral fins are reddish, the back is brown, and the sides are yellow, marbled with black. It has three spines in the anterior dorsal fin, and a fourth spine on the top of the operculum, with a small poison-sac at the base of each.
Next to this genus come the species of Thalassophryne, T. reticulata (fig. 111), found on the shores of Panama, and T. maculosa, of Bahia (Brazil), which are provided with a precisely similar poison-apparatus.
The physiological action of the venom of these two species has not yet been studied, but it is probable that it does not differ from that of the venom of the Weevers and the species of Synanceia.
Fig. 112.—Lophius setigerus (China Sea and Sea of Japan). (After Savtschenko.)
6.—Pediculati.
The fishes belonging to this family are of large size and compact shape, with the anterior part of the body greatly expanded. The head, which is broad, bears venomous spines, and the mouth is furnished with large teeth. These fishes are voracious, and lie in wait for their prey at the bottom of the water in the mud of the shore. In order to attract it, they make use of cutaneous appendages attached to their spines, which they are able to elevate, and of filaments situated near the mouth.
The principal genus is Lophius, one species of which, L. setigerus ([fig. 112]), is found in the seas of China and Japan. Another species, L. piscatorius (the Sea Devil or Angler), occurs in the temperate climates of Europe, North America, Asia and Africa.
Certain other Acanthopterygii are capable of inflicting wounds, but, although fishermen often believe them to be venomous, or such properties are frequently attributed to them in stories, it is doubtful whether they possess poison-glands. The accidents produced by them are due rather to the fact that the spines in their fins are extremely sharp, and that their flesh is toxic. Those belonging to the Percidæ (the Perch family), especially the genus Serranus and S. ouatabili ([fig. 113]) in particular, are above all remarkable in this respect. The last-mentioned fish has two or three spines on its operculum.
Fig. 113.—Serranus ouatabili. (After Savtschenko.)
The same may be said of certain Squamipinnes, another family of Acanthopterygii, whose stout bodies are brightly coloured, and have very sharp, spiny rays in their dorsal and anal fins. The most curious genus among the fishes belonging to this family is Holacanthus, in which the præoperculum is provided with an enormous spine like that of the Weever. Holocanthus imperator ([fig. 114]) is met with fairly often in the Indian Ocean and Malay Archipelago.
Fig. 114.—Holacanthus imperator (Indian Ocean and Malay Archipelago). (After Savtschenko.)