OCEANIC MAMMALS 425 



(2) Phocidae, true seals or hair seals. These are more highly 

 specialized for aquatic life than the sea-lions. The seals occur 

 along the shores of all seas and oceans, and certain forms are 

 found in the Caspian Sea and in Lake Baikal in central Asia. 

 Seven species are threatened with extinction. 



(3) Odobenidae, walruses. Two species of the single Recent 

 genus are recognized; both are endangered by hunting activi- 

 ties, although they are still represented by large herds in the 

 Arctic Ocean. J. E. H. 



Family OTARIIDAE: Sea-lions, Fur Seals 



SOUTHERN FUR SEAL 

 ARCTOCEPHALUS AUSTRALIS (Zimmermann) 



Phoca australis Zimmermann, Geographische Geschichte, vol. 3, p. 276, 1782 (Falk- 

 land Islands, based on Pennant's account). 



SYNONYMS: For full synonymy see J. A. Allen, 1905, who gives among important 

 synonyms the following: Phoca falklandica Shaw, General Zool., vol. 1, pt. 2, p. 

 256, 1800; Arctocephalus ursinus Gray, List Spec. Mamm. Brit. Mus., p. 103, 

 1843; Arctocephalus nigrescens Gray, Zool. Voy. Erebus and Terror, and Proc. 

 Zool. Soc. London, 1859, pp. 109, 360: 



FIGS.: Townsend, in Jordan et al., 1899, vol. 3, pi. 35; Allen, J. A., 1905, pi. 15, fig. 1; 

 pi. 16, fig. 2; pi. 17, fig. 2 (skull). 



The fur seals of the genus Arctocephalus are allied to the 

 North Pacific species of the genus Callorhinus but are dis- 

 tinguished by having the facial portion of the skull slender, 

 narrow, and elongated, with the upper profile sloping instead 

 of nearly flat, the molars larger. The several isolated groups 

 are in some cases regarded as separate species, but the differ- 

 ences are based largely on skull characters. All have been 

 much hunted for their pelts and are largely depleted or even 

 on the verge of extinction in parts of their range. 



The pelage is of two kinds a long, coarse, blackish overhair, 

 tipped with gray or yellowish gray, giving a grizzled effect, 

 except on the lower surface; and a thick, soft, brownish under- 

 fur, lighter at the tips and darker basally. Skull short and 

 broad, the brain case rather squarish, the antorbital region 

 very short, with short nasals; sagittal crest slightly developed. 

 Unworn teeth tricuspid, with a main cusp and small anterior 

 and posterior cusps. Teeth relatively much smaller than in 

 A. philippii. Basal length of skull, 235 mm. ; zygomatic width, 



