EVIDENCE FROM PALEONTOLOGY 101 



the fibula has been suppressed, its two extreme ends 

 remain and in the adult are indistinguishably fused 

 with the tibia. The feet are very long and have but 

 a single functional toe each, which is greatly en- 

 larged and strengthened to bear the heavy weight. 

 This remaining toe is the median one, or third, of 

 the original five, and the splint-bones are remnants 

 of the second and fourth, but have no joints or 

 hoofs attached to them, and are not visible in the 

 living animal. The horses walk on the very tips 

 of their toes and the curious, box-like hoof, which 

 encloses the terminal joint of the single functional 

 toe, is highly characteristic. 



In surveying the history of the changes which 

 lead back from the Recent horses to their far distant 

 ancestors of the lower Eocene, it will be necessary 

 to omit most of the stages, for lack of time, and 

 mention only the most obvious. Passing back to 

 the lower Pliocene and upper Miocene, we find that 

 the horses of those times, while unmistakably equine, 

 differed in certain very significant ways from their 

 modern descendants. They are decidedly smaller 

 and of more slender and deer-like proportions; their 

 grinding teeth are hardly more than half as high 

 proportionately and with masticating surfaces of 

 similar, but less complicated pattern. The feet are 

 three-toed, the lateral toes (second and fourth) 

 having a full complement of joints and carrying 

 hoofs, but were more dew-claws, not reaching the 

 ground, and could have been of service only in soft 



