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.