THE PKOBOSCID.E, OR ELEPHANTS. 239 



cliiu'd, with Weinsheimer, to assume only one 

 species, the Dinotherium ; we are also glad to be 

 reminded by him of Suess' words : ' We can readily 

 convince ourselves that physical changes occur 

 without the mammal of the district being much 

 affected by them, but we find no change in the 

 animal world without a change in the outward 

 circumstances, without some recognisable episode.' 

 The changes in the dentition of the Dinotherise 

 (which appear somewhat earlier than the masto- 

 dons) to the elephants proper, correspond with the 

 gradual change in their food and mode of life. 

 The Dinotheriae and the older mastodons had to 

 subsist mainly upon the roots and stalks of water- 

 plants, which they tore up with their lower tusks 

 in the morasses of tropical climes, like the rhinoce- 

 roses. Harder grasses demanded and produced 

 the transformation of the simple ridged tooth, 

 the tuberculate teeth of the mastodons, the fall- 

 ing away of the front milk-teeth, and finally a 

 concentration of the material force, and more 

 especially the peculiar conformation of the molar 

 of the later and present elephants. 1 They certainly 



1 ' All the changes of the organisation which we may observe 

 in the later forms of Mastodon as compared with the earlier 

 ones for instance, the different forms of the incisors, the re- 

 duction of the symphysis (i.e. the connecting parts of the lower 



