Almost equally widely distributed is the smaller remora, or shark-sucker (Echeneis remora), with a stouter body and about 18 plates in the cephalic disk. This species is found in Europe, on the coast of New York, in the West Indies, in California, and in Japan, but is nowhere abundant. Another widely distributed species is Remorina albescens with 13 plates in its disk. Remoropsis brachyptera, with 15 plates and a long soft dorsal, is also occasionally taken. Rhombochirus osteochir is a rare species of the Atlantic with 18 plates, having the pectoral rays all enlarged and stiff. The louse-fish (Phtheirichthys lineatus) is a small and slender remora having but 10 plates in its disk. It is found attached, not to sharks, but to barracudas and spearfishes.
Fig. 424.—Rhombochirus osteochir (Cuv. & Val.). Wood's Hole, Mass.
A fossil remora is described from the Oligocene shales in Glarus, Switzerland, under the name of Opisthomyzon glaronensis. It is characterized by the small disk posteriorly inserted. Its vertebræ are 10 + 13 = 24 only. Dr. Storms gives the following account of this species:
"A careful comparison of the proportion of all the parts of the skeleton of the fossil Echeneis with those of the living forms, such as Echeneis naucrates or Echeneis remora, shows that the fossil differs nearly equally from both, and that it was a more normally shaped fish than either of these forms. The head was narrower and less flattened, the preoperculum wider, but its two jaws had nearly the same length. The ribs, as also the neural and hæmal spines, were longer, the tail more forked, and the soft dorsal fin much longer. In fact it was a more compressed type, probably a far better swimmer than its living congeners, as might be expected if the smallness of the adhesive disk is taken into account."
Concerning the relations of the Discocephali Dr. Gill has the following pertinent remarks:
"The family of Scomberoides was constituted by Cuvier for certain forms of known organization, among which were fishes evidently related to Caranx, but which had free dorsal spines. Dr. Günther conceived the idea of disintegrating this family because, inter alias, the typical Scomberoides (family Scombridæ) have more than 24 vertebræ and others (family Carangidæ) had just 24. The assumption of Cuvier as to the relationship of Elacate (Rachycentron) was repeated, but inasmuch as it had 'more than 24 vertebræ' (it had 25 = 12 + 13) it was severed from the free-spined Carangidæ and associated with the Scombridæ. Elacate has an elongated body, flattened head, and a longitudinal lateral band; therefore Echeneis was considered to be next allied to Elacate and to belong to the same family. The very numerous differences in structure between the two were entirely ignored, and the reference of the Echeneis to the Scombridæ is simply due to assumption piled on assumption. The collocation need not, therefore, longer detain us. The possession by Echeneis of the anterior oval cephalic disk in place of a spinous dorsal fin would alone necessitate the isolation of the genus as a peculiar family. But that difference is associated with almost innumerable other peculiarities of the skeleton and other parts, and in a logical system it must be removed far from the Scombridæ, and probably be endowed with subordinal distinction. In all essential respects it departs greatly from the type of structure manifested in the Scombridæ and rather approximates—but very distantly—the Gobioidea and Blennioidea. In those types we have in some a tendency to flattening of the head, of anterior development of the dorsal fin, a simple basis cranii, etc. Nevertheless there is no close affinity, nor even tendency to the extreme modification of the spinous dorsal exhibited by Echeneis. In view of all these facts Echeneis, with its subdivisions, may be regarded as constituting not only a family but a suborder.... Who can consistently object to the proposition to segregate the Echeneididæ as a suborder of teleocephalous fishes? Not those who consider that the development of three or four inarticulate rays (or even less) in the front of the dorsal fin is sufficient to ordinarily differentiate a given form from another with only one or two such. Certainly the difference between the constituents of a disk and any rays or spines is much greater than the mere development or atrophy of articulations. Not those who consider that the manner of depression of spines, whether directly over the following, or to the right or left alternately, are of cardinal importance; for such differences, again, are manifestly of less morphological significance than the factors of a suctorial disk. Nevertheless there are doubtless many who will passively resist the proposition because of a conservative spirit, and who will vaguely refer to the development of the disk as being a 'teleological modification,' and as if it were not an actual fact and a development correlated with radical modifications of all parts of the skeleton at least. But whatever may be the closest relations of Echeneis, or the systematic value of its peculiarities, it is certain that it is not allied to Elacate any more than to hosts of scombroid, percoid, and kindred fishes, and that it differs in toto from it notwithstanding the claims that have been made otherwise. It is true that there is a striking resemblance, especially between the young—almost as great, for example, as that between the placental mouse and the marsupial Antechinomys—but the likeness is entirely superficial, and the scientific ichthyologist should be no more misled than would be the scientific therologist by the likeness of the marsupial and placental mammals."
Suborder Tæniosomi, the Ribbon-fishes.—The suborder Tæniosomi (ταινία, ribbon; σῶμα, body), or ribbon-fishes, is made up of strange inhabitants of the open seas, perhaps aberrant derivatives of the mackerel stock. The body is greatly elongate, much compressed, extremely fragile, covered with shining silvery skin. The ribbon-fishes live in the open sea, probably at no very great depth, but are almost never taken by collectors except when thrown on shore in storms or when attacked by other fishes and dragged above or below their depth. When found they are usually reported as sea-serpents, and although perfectly harmless, they are usually at once destroyed by their ignorant captors. The whole body is exceedingly fragile; the bones are porous, thin, and light, containing scarcely any calcareous matter. In the Tæniosomi the ventral fins are thoracic, formed of one or a few soft rays. More remarkable is the character of the caudal fin, which is always distorted and usually not in line with the rest of the body. The teeth are small. The general structure is not very different from that of the cutlass-fishes, Trichiuridæ, and other degraded offshoots from the scombroid group. The species are few and, from the nature of things, very imperfectly known. Scarcely any specimens are perfectly preserved. When dried the body almost disappears, both flesh and bones being composed chiefly of water.
The Oarfishes: Regalecidæ.—The Regalecidæ, or oarfishes, have the caudal fin obsolete and the ventrals reduced to long filaments, thickened at the tip. The species reach a length of twenty or thirty feet, and from their great size, slender forms, and sinuous motion have been almost everywhere regarded as sea-serpents. The very long anterior spines of the dorsal fin are tipped with red, and the fish is often and not untruthfully described as a sea-serpent "having a horse's head with a flaming red mane."
The great oarfish, Regalecus glesne (see Fig. 237, Vol. I) was long known to the common people of Norway as king of the herrings, it being thought that to harm it would be to drive the herring to some other coast. The name "king of the herrings" went into science as Regalecus, from rex, king, and halec, herring. The Japanese fancy, which runs in a different line, calls the creature "Dugunonuatatori," which means the "cock of the palace under the sea."