8 



conical, with very large single roots ; in some the last of the upper ones 

 have two roots, and small, compressed, lohed crowns ; head short, dog- 

 like ; muzzle enlarged, and furnished with strong, stiff whiskers ; ears 

 provided with a sub-cylindrical external conch ; eyes large, protected by 

 eye-lids ; mouth very large ; tongue forked at the extremity ; fore 

 limbs fin-like, situated far back ; hind limbs rather produced, com- 

 paratively free, and bent forwards in repose,- — the limbs evincing, by 

 their freer use, a nearer approach to the terrestrial Carnivora than 

 those of any other of the Seal tribe ; nails flat, small, slender ; 

 membrane of the feet prolonged beyond the nails into as many lobes 

 as there are toes ; tail short, conical ; mammae four, ventral ; males 

 much larger and darker in colour than the females. 



These animals, during progression on land, walk on their fore and 

 hind limbs, and in repose turn the hind feet forwards. In habits they 

 are gregarious and polygamous. 



SEALS, Adults, with abundant under-fur. 

 Qenus Aectocephaiits,' P. Cuvier. 

 Incisors ^, canine lij; molars s^ = 36. 



Upper incisors large, lower ones small; canines large, sharply 

 pointed. Head and face somewhat elongated ; cerebral region slightly 

 elevated; sagittal crest moderately developed ; muzzle narrow, pointed, 

 moderately enlarged between and above the nostrils ; body more 

 slender, feet and toe-flaps proportionately longer, than those of the 

 Sea Lion ; claws very small, scarcely visible ; toes of the hind feet 

 short, all nearly of the same length ; body covered with hair, and 

 with thick, permanent, under-fur. In size the Sea Bears are much 

 Bmaller than the Sea Lions. 



AECTOCEPHAirs TJEsmiTS,^ LiunsBus. Northern Pur-Seal of Commerce. 



Synonyms — Phoca ursina, Linn. 



Otaria ursina, Peron. Desm. ; Nilsson, G-ray, Peters. 

 Arotoceplialus ursinus, Gray, Gill. 



Arciocephalus Calif or nianus, G-ray, B. M. C. 1866, p. 51. 



Callorhinus ursinus. Gray, B. M. C. p. 44 ; Suppl. 1871, 



p. 14 ; Allen, Bull. Mus. Comp., vol. ii., p. 73. 



The Northern and Southern Pur-Seals are considered by Dr. Gray 



to be generically distinct ; the skull of the former (Callorhinus)^ "being 



easily known" from the latter (Arctocephalus) " by the shortness of 



the face, and convexity of the nose." 



It must be borne in mind, that even in the same species the develop- 

 ment of the skull exhibits marked sexual characters, as well as many 

 of those diff'erences of form which occur during the various periods of 

 growth. So frequently are these cranial variations met with, that it 



^ &pKTos, a bear, and Ke<pa\-f], the head — bear-headed. 



■^ Ursinus, bear-like. 



' KoKKos beautiful, and liivos ekin. 



