40 JUDGING FARM ANIMALS 



third bone, and the hoof to its nail. The navicular bone 

 has no counterpart in our frame. In the hind limb, the 

 stifle represents our knee; the tibia, the shin; the hock, 

 the ankle; the point of the hock, the heel; and so on. In 

 man, the fibula 'is a fully developed bone. We may thus 

 see that the horse is an animal that moves on the tips of 

 his fingers and toes ; and that he has only one complete and 

 functional toe to each leg." 



The relationship of speed in the horse to the structure 

 of the skeleton is an important one. The prehistoric horse 

 possessed five toes instead of one on each foot. During 

 the process of evolution, the excess side toes disappeared, 

 leaving only the central one and two more or less developed 

 splints; the cannon bone also increased in length. Ac- 

 cording to Lydekker * this development to a one-toe basis, 

 with the accompanying splints, the elongation of the bones 

 of the lower part of the limb, the simplification and the 

 consolidation of the middle part, and the raising of the 

 knee and hock far above the level of the ground, so as to 

 cause the animal to walk on the tips of its single toes, are 

 the important features wherein the horse, as compared 

 with other animals, is adapted to high speed. At the 

 present day the horse is the only animal having a single 

 toed or monodactyle foot. A many toed, short boned limb,i 

 would be unequal to the strain of carrying the body of such| 

 a heavy animal at a high rate of speed over hard ground.' 



The muscles of the body consist of groups of fleshy fiber, 

 that under the influence of the nerves, have the power to 

 contract. Most of the muscles are attached to bone by 

 means of tough, hard, whitish cords, known as tendons. 

 Through direction from the brain, the nervous system 

 stimulates the muscle which at once contracts and thus 

 produces power. Muscles differ in length and strength, 

 short, thick ones being capable of producing greater strength 

 than long, slender ones. The tendons also differ in length 

 and degree of attachment to the bone. A muscle can con- 



* The Horse and its Relatives, London, 1912, p. 17. 



