4 THE HOHSE IN AMERICA 



nishes one of the most interesting examples of 

 evolution. When he had five toes he lived in low- 

 lying, marshy land and the toes were needed so 

 that he could get about. He had a short neck and 

 short jaws, as longer were not needed to enable 

 him to feed on the easily reached herbage. As the 

 earth became harder, the waters receding, his 

 neck and jaws lengthened, as it was necessary for 

 him to reach further to crop the less luxuriant and 

 shorter grasses. He lost, also one toe after another 

 so that he might travel faster and so escape his 

 enemies. These toes, of course, did not disappear 

 all at once, but grew shorter, until they hung 

 above the ground. The "splint bones" on a 

 horse's legs are the remains of two of these once 

 indispensable toes, while the hoof is the nail of the 

 last remaining toe. 



As the neck of the horse grew longer and two 

 toes had been dropped, the legs lengthened and 

 by the time he became what the scientists call a 

 " Neohipparion " he was about three feet high, 

 and his skeleton bore a very striking resemblance 

 to that of the horse of to-day. The teeth also 

 changed with the rest of the animal. In the earli- 



