372 LAND MAMMALS IN THE WESTERN HEMISPHERE 



4. '\Oreodontidce. f Oreodonts 



This was one of the most characteristic of North American 

 artiodactyl famiUes, and its members were exceedingly abun- 

 dant throughout the upper Eocene, the whole Oligocene and 

 Miocene, ending their long career in the lower Pliocene. In 

 distribution the family was exclusively North American, and 

 no trace of it has been found in any other continent. In the 

 course of their long history the foreodonts underwent many 

 transformations and branched out into several distinct phyla, 

 yet through all these changes they remained singularly con- 

 servative, for the transformations, some of them sufficiently 

 bizarre, affected chiefly the teeth and skull, the remainder of 

 the skeleton changing but little. The foreodonts were all 

 small or of moderate size, none of them surpassing the Wild 

 Boar in stature, nor was there any decided increase in size 

 from stage to stage. One and all, they were strange beasts. 

 Dr. Leidy, who first described and named most of the genera, 

 spoke of them as combining the characters of camel, deer and 

 pig, and called them "ruminating hogs," a conception expressed 

 in the names which he gave to some of them, such as '\Merychyus 

 and '\Merycochoerus, both of which mean ruminant swine. 



The general proportions of most of the species were quite 

 as in the peccaries, though, for the most part, with much longer 

 tails ; they had a short neck, elongate body, short limbs and 

 feet. In one genus (fMesoreodon) of the lower Miocene a 

 rudimentary collar-bone has been found, and probably all of 

 the more ancient genera possessed it, but only by an unusually 

 lucky chance would so small and loosely attached a bone be 

 preserved in place. As the collar-bone is superfluous in hoofed 

 animals, in which the limbs are used only for locomotion and 

 move in planes parallel with that of the backbone, it is almost 

 universally absent in them, and in only one other group of 

 ungulates, the extinct fTypotheria of South America, has its 

 presence been demonstrated. In all of the foreodonts the 



