354 LAND MAMMALS IN THE WESTERN HEMISPHERE 



Miocene, and the middle Eocene respectively, being at all 

 adequately known, but even in this imperfect form the story 

 is worth telling. The suborder was probably of American 

 origin and its most ancient known member existed in the middle 

 Eocene. Both in Europe and North America the group per- 

 sisted into the lower Pliocene and it is believed, though not 

 clearly demonstrated, that in eastern Asia it continued even 

 into the Pleistocene. All the genera of the suborder may be 

 included in a single family. 



7. ^Chalicotheriidce. ^Chalicotheres 



The specimens which so far have been found in the Ameri- 

 can middle and upper Miocene and lower PUocene are very 

 fragmentary, consisting of little more than teeth, and give 

 no information other than to demonstrate the presence of the 

 family in North America during that period of time. On the 

 other hand, the European genera of the middle Miocene and 

 lower Pliocene are well known and may or may not have 

 been closely similar to their American contemporaries, though 

 they were undoubtedly larger. In these most peculiar and gro- 

 tesque animals {^Macrotherium and ^Chalicotherium) the head 

 was relatively small, the teeth were very low-crowned and 

 adapted only to a diet of soft vegetable substances and the 

 mode of feeding must have been that of browsing upon leaves 

 and shoots of trees and bushes ; the premolars had not acquired 

 the molar-pattern, which was very exceptional for perisso- 

 dactyls of' so late a time, such a difference between the two 

 classes of teeth being characteristic of the Eocene members 

 of the order; the incisors and canines were reduced, but the 

 formula is not definitely known. 



The neck was of moderate length, the body very long, and 

 the limbs were also elongate, especially the anterior pair, in 

 consequence of which the back sloped downward from the 

 shoulders to the rump ; the two fore-arm bones were fused 



