LIFE OF TERTIARY PERIOD 



247 



appearance of the living animal, here reproduced from his book. 

 (Fig. 84.) The trunk could not therefore have hung down 

 as in the modern elephants, and it seems hardly likely that 

 with such tusks a trunk would have been developed. If a short 

 one had been formed it would probably have been for the 

 purpose of drinking and for pushing food into the mouth side- 

 ways. It is most interesting to see how the difficulty was 



Fig. 85. — Skeleton of Mastodon Americanus. 

 From the Pleistocene of Missouri, U.S.A. Length, 20 feet; height, 9% feet. 



(B.M. Guide.) 



overcome. In the next stage both pairs of tusks have become 

 straightened out, the lower ones much reduced in length and 

 the chin also somewhat shortened. That this process went on 

 step by step is indicated by the ^lastodons, which are elephants 

 with a simpler form of teeth, and a pair of tusks like all living 

 and recently extinct elephants (see Fig. 85). But when very 

 young the American Mastodon had a pair of short tusks in the 

 lower jaw, which soon fell out. In the character of its teeth 

 generally, the Mastodon agrees with Tetrabelodon (wliich was 

 originally classed as a Mastodon) ; and there are Indian extinct 



