HISTORY OF THE HORSE 



6i 



slender than in the earlier stages and are uselt.ss, as they 

 do hot reach the ground. In some species of Pliohippus 

 thty have almost disappeared. The forefoot of Proto- 

 hippus still retains small nodules of bone, which are the 



Fig. 49.— changes in the legs and feet showing evolution 



remains of the first and fifth toes. The animals of this 

 period vs^ere about 40 inches high. 



12. Equiis. — From the Pleistocene and Recent. This is 

 the stage of the modern horse. The side toes have dis- 

 • appeared and are represented by splints on the fore and 

 hind foot. No trace remains on the forefoot of the small 

 nodules, which in Protohippus represented the first and 

 fifth toes. The crowns of the teeth are much longer, and 

 of the two half-separated inner columns on the upper 

 molars, one has disappeared, while the other has increased 

 in size and changed in form. The skull has lengthened 

 and the animal is much larger. 



Meaning of the change in feet and teeth. — Along with 

 the disappearance of the side toes there is considerable 

 increase in the length of the legs, especially of the lower 

 part. The surface of the joints, at first more or less of 



