ANIMALS OF THE PAST 



337 



teeth were rather degenerate, indicating a prehensile upper 

 lip, and the second pair of incisors in each jaw were some- 

 what developed as tusks. In the Upper Eocene this 



FIG. 114. Showing fossil ancestors and living representatives of elephant and 

 horse. ( After Lull.) 



primitive elephant (Mceritherium) was asssociated with a 

 more specialized type (Palceomastodon, B) of somewhat 

 larger size. This new elephant had a greatly elongated 



