EXTINCT ANIMALS 



ankle and the carpus or wrist (so-called " knee " 

 of the horse's front-leg) respectively. You see, 

 the horse walks on the very last joint of its toes, 

 and keeps the foot and the hand upright, so 

 that the heel is right above the toe instead of 

 behind it, as in ourselves and the bears. On 

 each side of the long bone of both fore and hind- 

 foot you will see a small long bone, narrow and 

 delicate. The nearer one of these delicate bones 

 is not very clearly shown in the photograph, 

 but still can be made out. These delicate 

 " splint-bones," as they are called, are all that 

 remain in the modern horse of two additional 

 toes. There was a time when horses had three 

 toes — far back in the Miocene strata we find 

 horses which had three well-developed toes, each 

 with a hoof resting on the ground (the Meso- 

 hippus and Anchitherium), and earlier than 

 that we find a horse-like creature (Hyraco- 

 therium) with three nearly equal-sized toes on 

 the hind-foot and four on the front foot (Fig. 

 92). In the Pliocene we find a three-toed 

 horse in Europe known as the Hipparion (and 

 a similar kind is dug up in America), which had 

 three toes on each foot ; but the side toes were 

 getting small, were in fact like the " petti-toes " 



136 



