THE ARCTOG^IC REALM. [CHAP. 



family (Coryphodontidce] common to the lower Eocene of both 

 hemispheres, while a second family ( Uintatheriid<z), of later age is 

 strictly North American. All these animals had limbs of an 

 elephantine type, each foot being furnished with five toes, and the 

 bones of the wrist and ankle joints arranged on the linear plan. 

 The genus Coryphodon, which includes species varying in size 

 from a tapir to a rhinoceros, had forty-four teeth, with the canines 



FIG. 43. LEFT UPPER CHEEK-TEETH OF Coryphodon ; reduced. 



well developed, and the molars bearing prominent oblique ridges. 

 First discovered in the London Clay, and subsequently in the 

 lower Eocene of France, this genus has since been recognised in 

 the lower Eocene of the United States, where nearly perfect 

 skeletons have been obtained. 



In a still more primitive group known as the Condylarthra, 

 which apparently contains the ancestral stock of both the artio- 

 dactyles and perissodactyles, it is believed that the genus Phena- 

 codus (the ultimate parent of the horses), typically occurring in the 

 Wahsatch Eocene of the United States, is represented in the Swiss 

 Eocene; and the same has been stated to be the case with 

 Protogonia. 



Summarising the results of the foregoing survey, it may be 

 stated that as regards its mammalian fauna Arctogaea 



Summary of . 



the character- as a whole is characterised by the following features, 

 mammalian Absence of monotremes and diprotodont marsu- 

 faunaof Arcto- pials. No existing polyprotodont marsupials except 

 opossums, and these only in its western half. No 

 Tertiary marsupials known except opossums, although other types 

 probably existed in South-eastern Asia. No existing edentates 1 , 

 and fossil ones only in North American Plistocene and Pliocene. 

 No marmosets (Hapalida), and no monkeys of the family Cebidce. 

 Bats of the family Phyllostomatida wanting, save for a few on the 

 1 The aard-varks and pangolins are here excluded from the Edentata. 



