304 THE ARTISTIC ANATOMY OF ANIMALS 



in that the foot-faUings of each diagonal biped occur at 

 slight intervals, and give distinct sounds. The notation is 

 reproduced in Fig. 136. 



The Leap. — The leap is an act by which the body is 

 wholly raised from the ground and projected upwards and 

 forwards to a greater or less distance. 



It is prepared for by the flexing of the hind-limbs, which, 

 by being suddenly extended, project the body, and thus 

 enable it to pass over an obstacle. 



This preparatory arrangement is very remarkable in the 

 leap of the lion, the cat, and the panther, which execute 

 springs of great length ; in the horse, in which the leap 

 is not an habitual mode of progression, this flexion of the 

 hinder limbs is less marked. With this animal the leap is 

 generally associated with the gallop ; nevertheless, it is 

 sometimes made from a stationary position. In observing 

 the hare or the rabbit, in which the leap is habitual, we 

 notice (Fig. 137) that the hind-limbs, being extremely 

 flexed, rest on the ground as far as the calcaneum, are 

 then straightened by the action of their extensors, become 

 vertical and then oblique backwards at the moment the 

 body is thrown forward into space by the sudden extension 

 of these limbs. 



The action of the extensors is energetic and instan- 

 taneous, and their energy is greater than in ordinary pro- 

 gression, for it is required to lift the body and to project 

 it forcibly a more or less considerable distance. It is 

 the extreme rapidity of this action which enables the 

 animal to clear an obstacle, for without this condition 

 the body would be raised, but not separated from the 

 ground. 



First of all, in reaching the obstacle to be cleared, the 

 horse prepares to leap by taking the attitude of rearing ; 

 the hind-limbs are flexed and carried under the body, the 

 fore-quarters are raised, and the different segments of the 

 fore-limbs are flexed (Fig. 138). 



One sudden trigger action produced by the violent con- 

 traction of the extensors of the hind-legs then takes place, 

 and the animal is projected forwards, while he flexes the 



