ANIMAL LOCOMOTION. 49 



the goat, which has but two functionally active toes, the outer of 

 the two is deflected. 



The action of the toes must be studied in connection with the 

 outward rotation. It is evident that the outward rotation must 

 be at an end, or near an end, before the digits are taken from the 

 ground. (See rotation in elephant, p. 90.) 



THE ACTION OF THE LIMB WHEN GOING OFF 

 THE GROUND AND WHEN IN THE AIR. 



The first movement noticed in the limb after it is beyond the 

 centre of gravity is the flexion of the foot. In the horse the 

 hoof is thrown backward, and the under surface of the foot is 

 directed backward, the heel being raised first. The sole is next 

 directed upward. In animals possessing more than one function- 

 ally active toe the toes are quickly adducted in the air, so as to 

 offer the least resistance to the impetus of the entire body. Asso- 

 ciated with the above, a pronounced flexion of all parts of the 

 limb occurs excepting at the hip, where the movement is slight. 

 A movement of the thigh towards the trunk is faintly discernible. 

 In animals possessing long thigh-bones, such as the elephant, the 

 movement is more decided than in hoofed animals. The same 

 remarks are applicable to the movements of the humerus. The 

 degree to which flexion is carried is more marked in the young 

 than in the adult, and in terrestrial than in arboreal creatures. In 

 the sloth [Choloejms) flexion is absent, the limbs being advanced 

 by a swinging motion at the shoulder and the hip. (Fig. 11, p. 83.) 

 In rapid gaits the unaided eye receives the impression of backward 

 movement, but fails to be impressed with forward movement. It 

 may hence be inferred that the former is a quicker movement 

 than the latter. 



In the fore limb the last state of extension of the forearm 

 answers to the action of the extensors of the carpus and of the 

 digits. In the less delicate movements of the hind limb the 

 muscles which extend the tarsus and the toes move the foot with 

 less precision, and, it is likely, with less speed. The first stage of 

 the recover is a deliberate act. Beginning at the toes, it ends at 

 the hip. The second stage is quicker than the preceding and is 

 more abrupt. Beginning at the hip, it ends at the toes. 



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