GEOGRAPHICAL DISTRIBUTION. 65 



nearest living allies, by the geological evidence of their antiq- 

 uity as by the actually observed and admittedly slight differ- 

 ences of form and structure. Mr. Lankester does not inform us 

 respecting the locality whence came his specimens of the tusks 

 of the living Walrus with which he compared the fossil tusks. 

 In this connection it may be added (see further on this point the 

 account of Odobcenus obesus given beyond) that the tusks of the Pa- 

 cific species ( Odobcenus obesus) are not only longer and slenderer 

 than those of the Atlantic species (0. rosmarus), but are sharper- 

 pointed and more incurved, and do not present the worn and 

 broken appearance so often (indeed, usually) seen in the tusks 

 of old individuals of the latter. Whether or not they present 

 differences of structure has not, so far as known to me, been 

 microscopically determined. The tusks of the Pacific species, 

 furthermore, sometimes attain the size indicated for the tusks 

 of " Trichecodon Uuxleyi." For the present I must consider Lan- 

 kester's Tricliecodon huxleyi as certainly not generically separ- 

 able from the existing Walruses, although it may have differed 

 from the existing Atlantic species in larger size and possibly in 

 other characters, as so often happens among the immediate pro- 

 genitors of existing species in other groups of mammals. 



Van Beneden has recently reviewed at considerable length 

 the history of the supposed and actual fossil remains of the 

 Walrus,* showing that most of those reported as found in differ- 

 ent parts of France and Germany were really those of different 

 species of extinct Sirenians or other animals than the Walrus. 

 Van Beneden, however, describes and figures a dorsal vertebra 

 he considers as that of the Walrus, found near Deurne, and a sca- 

 phoid bone from Anvers. 



GEOGRAPHICAL DISTRIBUTION, PRESENT AND PAST. 1. 

 Coast of North America. As already shown (antea, pp. 57-61), the 

 Walrus, like the Musk Ox, the Caribou, and the Moose, ranged 

 during the great Ice Period much beyond the southern limit of 

 its boundary at the time the eastern coast of North America 

 was first visited by Europeans. While its remains have been 

 found as far south as New Jersey, Virginia, and even South 

 Carolina, there is no evidence of its existence on the New Eng- 

 land coast within historic time, or during the last three hun- 

 dred and fifty years. During the last half of the sixteenth cen- 

 tury they are known to have frequented the southern coast of 



* Ann. Mus. d'Hist. Nat. de Belgique, i, 1877, pp. 3^-42. 

 Misc. Pub. No. 12 5 



