158 THE ARCTOG^IC REALM. [CHAP. 



Much the same story is told by the fossil dogs ( Canidce) of the 

 two areas. In the Miocene of North America we meet with the 

 genus Temnocyon, characterised by the cutting heel of the lower 

 carnassial tooth; while the more civet-like Cynodictis appears to be 

 confined to the Tertiaries of Europe. The bear-like genus Am- 

 phicyon, differing from modern dogs by its plantigrade feet, is 

 confined to the European Oligocene and Miocene and lower 

 Pliocene, but is represented in the Miocene of America by the 

 nearly allied Daphcemis. Through the intervention of the still 

 larger Dinocyon of the European Miocene, the foregoing groups are 

 intimately connected with the bears (Ursidcz) by means of the 

 genus Hycenarctus, which is common to the Miocene and Pliocene 

 of Europe and the Pliocene of India; and this suggests that the 

 bears are originally an Old World group, which have subsequently 

 migrated into America. As to whether true dogs (Cam's) and cats 

 (Felis) originated in America or Europe, we have no means of 

 deciding 1 . The large weasel family (Mustelidce) calls for no special 

 mention here, although its comparative poverty in South America 

 proclaims its Arctogaeic origin. 



The community between the mammalian faunas of Eastern 

 and Western Arctogaea is perhaps better exemplified by the ex- 

 tinct creodont carnivores, since none of the families occurring there 

 have been definitely recognised in the South American area. 

 Differing from modern carnivores by the absence of a pair of 

 differentiated carnassial teeth in each jaw, as well as by the 

 scaphoid and lunar bones of the wrist generally remaining 

 separate, and by the nearly flat upper surfaces of the astragalus in 

 the ankle, these creodonts make their first appearance in the 

 Puerco, and mostly died out in the Oligocene, although a few seem 

 to have survived till the Miocene. In the typical family Hyczno- 

 dontida we find the genus Hycenodon common to the Oligocene of 

 both sides of the Atlantic, while the European Pterodon seems to 

 have a transatlantic representative in the so-called Hemipsalodon of 



1 Scott, Trans. Amer. Phil. Soc. xvn. p. 75, concludes that the evolution 

 of Cam's took place in North America, the ancestry being traced through 

 Cynodesmtts of the John Day Beds to Daphcemis of the White River, and 

 thence to the creodont Miacis of the Bridger ; Cynodictis forming a lateral 

 branch. 



