The Rise of the Mammals 



stature of a collie dog, and they doubtless 

 formed a large part of the prey of the nu- 

 merous carnivores. 



Starting with the titanotheres, but coming 

 into prominence later, when they wandered 

 over the plains of Oregon and the lake region 



Skeleton of the great elothere, Elolherium crassum. 

 (After Marsh.) 



of South Dakota, were the Elotheres, a group 

 of great hog-like animals, represented also in 

 Europe. Some of these were no larger than a 

 wild boar; some, like Elotherium imperatw, 

 had heads nearly a yard long, the cheeks and 

 jaws adorned with great callosities like those 

 from which the modern wart-hog gains its name. 



241 



