The Evolution of the Horse 



bones of veterinarians answer to the joints of 

 our middle fingers, while the hoof is simply a 

 greatly enlarged and thickened nail. But if 

 what lies below the horse's "knee" thus cor- 

 responds to the middle finger in ours, 

 what has become of the four other lingers or 

 digits? We find in the places of the second 

 and fourth digits only two slender splint-like 

 bones, about two-thirds as long as the cannon 

 bone, which gradually taper to their lower ends 

 and bear no finger joints, or, as they are termed, 

 phalanges. Sometimes, small bony or gristly 

 nodules are to be found at the bases of these 

 two metacarpal splints, and it is probable 

 that these represent rudiments of the first 

 and fifth toes. Thus, the part of the horse's 

 skeleton, which corresponds with that of the 

 human hand, contains one overgrown middle 

 digit, and at least two imperfect lateral digits; 

 and these answer, respectively, to the third, 

 the second and the fourth fingers in man. 



Corresponding modifications are found in 

 the hind limb. In ourselves, and in most quad- 

 rupeds, the leg contains two distinct bones, 

 a large bone, the tibia, and a smaller and more 

 slender bone, the fibula. But, in the horse, 

 the fibula seems, at first, to be reduced to its 

 upper end; a short slender bone united with 

 the tibia, and ending in a point below, occupying 

 its place. Examination of the lower end of a 

 young foal's shin-bone, however, shows a dis- 

 tinct portion of osseous matter, which is the 

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