32 ELEPHANTS. 



three crests, like the anterior true molar. All the molars and 

 premolars remain in use throughout the animal's life, a condition 

 already lost in the earliest Tetrabelodons. It has been suggested 

 that Dmotherium was an aquatic animal, but there is nothing 



Fig. 19. 



Mandible of a young individual of Mastodon americanus, showing the small 

 remnants of the lower incisors. In the adult these are lost. From a 

 Pleistocene deposit, North America. About % nat. size. 



in the structure of the limbs to give any support to this idea > 

 though the lowness of the crowns of the teeth probably 

 indicates that it lived on soft herbaceous vegetation, such as 

 may have grown in swampy places. 



