On the Sharks of the Family Squalidfe. 39 EXPLANATION OF PLATE V. Fiy. 1. Atyloides aucklandicus, sp. n. First gnathopod. Fig. 2. Ditto, young. First gnathopod. Fty. 3. Aucklandia enderbi/i, sp. n. First gnathopod. Fiff. 4. Ditto. Second gnathopod. Fiy. 0. Hyale triyonuchir, sp. u. First gnathopod, male. Fiy. 6. Ditto. Second gnathopod, male. Fiy, 7. Ditto. Second gnathopod, female. VII. — A Synopsis of the Sharks of the Family Sqiialidai. By C. Tate Regan, M.A. The Squalidge may be diagnosed as sharks without an anal fin, with five or six gill-openings on each side, the last in front of the base of the pectoral fin, which is normally shaped, and with the mouth inferior. Fourteen genera may be recognized. Synopsis of the G'enera. T. Snout normal, not produced into a saw-like rostrum. (^Squalince.) A. Mouth crescentic. Each dorsal fin preceded by a spine 1. Centroscy Ilium. No fin-spines 2. Echinorhinus. B. Mouth transverse, but little arched, with a straight oblique groove on each side. 1. Mouth rather small; body trihedral, the flat lower surface margined on each side by a strong dermal fold ; dorsal fin-spines present o. Oxynotus. 2. Mouth wide ; body elongate, subcylindrical. a. Each dorsal tin preceded by a spine, which may project or may be small and concealed. Teeth in the upper jaw erect, tricuspid or peuta-cuspid ; lower teeth oblique, unicuspid, with points strongly deflected laterally 4. Sinnax. Teeth in both jaws oblique, unicuspid, with points strongly deflected laterally 5. Squalus. Upper teeth erect, lanceolate, two-rooted : lower teeth erect, triangular 6. Scymnodon. Upper teeth erect, lanceolate, two-rooted ; lower teeth oblique, with points deflected laterally. . 7. Centroscymuus^ Upper teeth erect or somewhat oblique, triangular, with quadrate bases ; lower teeth oblique, with points deflected laterally 8 Centrophorus.
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