180 THE STEUCTUEE OF THE HOESE. 



face of the fore limb of the horse below the so-called 

 "knee"), we see slight prominences just behind the 

 root of each finger and opposite the knuckles on the 

 back of the hand, which mark the position of the 

 joint between the metacarpal bones and the first 

 phalanges of the digits. Over these, especially when 

 the palm is subject to pressure and friction from 

 hard manual labor, the epidermis is somewhat thick- 

 ened. The sole of the foot presents exactly the same 

 arrangement. In such an animal as a dog or a cat, 

 in which this part of the foot comes to the ground in 

 walking, there is a large trilobed prominent, bare 

 pad (Fig. 23, B, 6), composed of a thick fatty cushion, 

 covered with a hardened epidermis, generally of a 

 black color. There are also smaller pads in front of 

 this on the under surface of each of the toes, but the 

 large one corresponds with the coalesced three middle 

 prominences of the human palm or sole just noticed. 

 In the horse's nearest living relatives, the tapir 

 and rhinoceros, the same arrangement holds good. 

 There is a large pad under the forepart of the middle 

 of the foot, which in these animals rests on the 

 ground, and also a hard sole under each toe (see Fig. 

 7, p. 47). Now the ergot of the horse clearly, both 

 by structure and position, corresponds to the palmar 

 or plantar pads of those animals which walk more or 

 less on the palm and sole. Owing to the modified 



