EVIDENCES OF EVOLUTION 29 



severest do not in the least impugn the doc- 

 trine of evolution. 



What seems clear is this, that in early 

 Eocene times there lived small five-toed 

 hoofed quadrupeds of generalized type, that 

 the descendants of these were gradually 

 specialized throughout long ages along similar 

 but by and by divergent lines, that they lost 

 toe after toe till only the third remained, 

 that they became taller and swifter, that they 

 gained longer necks, more complex teeth and 

 larger brains. So from the short-legged splay- 

 footed plodders of the Eocene marshes there 

 were evolved light-footed horses running on 

 tiptoe on the dry plains. 



We can only refer to the importance for an 

 evolutionist outlook of thus trying to corre- 

 late the changes in the animal with the 

 changes in the external conditions. The evo- 

 lution of the horse is wrapped up with the 

 evolution of the plains, and of their grasses 

 also, for these made their first appearance 

 in Tertiary times. The early ancestors prob- 

 ably lived in the warm luxuriant forests, 

 but as colder, drier climate set in, and the 

 forests shrank, the progressive "hippoids" 

 took more and more to the open. Even in 

 regard to the teeth we can understand that 

 the change from the short-crowned to the 

 long-crowned type enabled the animals, as 



