XIV FUR SEALS AND HAIR SEALS Asn 
in six genera; but more generic names have been proposed. At 
the other extreme stands Dr. Mivart, who speaks of only one 
genus, Ofaria; of this genus the number of species is by no 
means agreed upon. There can, however, be no doubt of the 
distinctness of the Northern Fur Seal, 0. wrsina (the “Seal” of 
commerce and the cause of international complications), of the 
Patagonian Maned Sea-Lion, 0. jubata,' of O. pusilla of the Cape, 
of the Californian O. gillespier, of O. hookert from the Auckland 
Islands, and of four or five others. The range of the genus is wide, 
but is mainly Antarctic. It is usual to speak of “ Hair Seals” 
and “ Fur Seals,” the latter being the species which produce the 
“sealskin” of commerce. The difference is that in the Fur Seals 
there is a dense, soft under-fur, which is wanting in the other group. 
It is, however, impossible to make this character the basis of a 
generic subdivision. There is a Fur Seal, 0. nigrescens, in South 
America as well as the more widely-known northern form. 
Fam. 2. Trichechidae.—This family contains but one genus, 
Trichechus, the Walrus or Morse, or Odobaenus, as the more 
correct term seems to be. It is a tiresome result of accurate 
conformity with the rules of priority in nomenclature that the 
name 7’richechus should be applied to the Manatee. There is but 
one species of Walrus, though it has been attempted to show that 
the Pacific and Eastern forms are different. The animal is Arctic 
and circumpolar. The Walrus is characterised by the enormous 
canines of its upper jaw, which form the well-known tusks and 
reach a length of 50 inches. The animal can progress on land 
like the Sea-Lions; but, as in the Seals, there are no external 
ears, though there is a slight protuberance above the meatus 
auditorius. The strong bristles upon the upper lip are as thick as — 
crow quills. The pectoral limb has nails, but these are small, as 
in the Sea-Lions. The under surface of the manus has a warty pad, 
which cannot but assist * in maintaining a foothold upon slippery 
ice. ‘The hind-limbs have longer nails, which are still diminutive 
and subequal in size. There is no free tail. The liver of this 
animal is much furrowed, but not so much so as in Otaria, though 
more so than in Phoca. The kidneys are of course lobulate, as in 
the other aquatic Carnivores. The milk dental formula appears to 
be 13 C1 Pm+M2. In the adult the formula’ is 13 C+ M3. 
1 Murie, Trans. Zool. Soc. vii. 1894, p. 411. 2 Cf. the Dugong, p. 336. 
3 Kukenthal, Jen. Zeitschr. xxviii. 1894, p. 76. 
