“The teeth of _Otaria jubata_ are subject occasionally to a peculiar wearing, of a median constricted character. “Between the female and male of this species there is a wide difference as regards the stretch of the pectoral flippers. In the skin of the male the breadth from tip to tip of the fore flippers is equal to or greater than the length of the body; in the female the reverse obtains. This fact points to greater strength and swimming-power of the former.” Sect. II. _The palate rather produced behind. The front edge of the hinder nasal opening in a line with the middle of the zygomatic arch._ Sea-bears. Tribe II. _CALLORHININA._ Grinders 6/5·6/5. Skull oblong; face broad, shorter than the orbit; forehead arched. See Cat. S. & W. p. 45, f. 16 (skull). Callorhinina, _Gray_, _Ann. & Mag. N. H._ 1869, vol. iv. p. 269. 2. CALLORHINUS. Skull elongate; forehead rounded in front of the orbit, rather swollen. Palate rather concave, as wide in front as at the end of the tooth-line, rather narrowed behind. The sixth upper grinder just behind the hinder edge of the zygomatic arch; the grinders moderate, fifth and sixth upper and the fifth lower with two diverging roots. Front flapper small, narrow. Flap of toes very long. Callorhinus, _Gray_, _P. Z. S._ 1859, p. 359; _Annals & Mag. N. H._ 1866, vol. xviii. p. 234; _Cat. S. & W._ p. 44, f. 16 (skull); _Peters_. Arctocephalus, _Gill_! 1. Callorhinus ursinus. _Northern Sea-Bear._ B.M. Phoca ursina, _Linn._; _Pander & D’Alton_, t. 7. f. 1 (not good). Otaria (Callorhinus) ursina, _Peters_, _Monatsb._ 1866, pp. 273 & 672. Otaria Stelleri (part.), _Lesson & Müller_. Callorhinus ursinus, _Gray_, _P. Z. S._ 1859, p. 359, t. 58 (skull); _Ann. & Mag. N. H._ 1866, xviii. p. 235; _Cat. Seals & W._ p. 44, f. 16 (skull); _Allen_, _Bull. Mus. Comp. Zool._ ii. pp. 44 & 73, tab. 2 & 3. figs. 1-8. Arctocephalus ursinus, _Gill_, _Proc. Essex Inst._ vol. v. 1866, p. 13 (not _F. Cuvier_). _Young._ Arctocephalus monteriensis, _Gray_, _P. Z. S._ 1859, p. 358 (skin only). Arctocephalus californianus, _Gray_, _Cat. Seals & Whales_, p. 51 (skin only). Inhab. Kamtschatka. B.M. Tribe III. _ARCTOCEPHALINA._ Grinders 6/5·6/5; face of the skull shelving in front; the fifth and sixth grinders behind the front of the zygomatic arch. 3. PHOCARCTOS.