THE ANTERIOR LIMBS OF QUADRUPEDS. 33 



apart from the ctest, and the arms, instead of 

 being drawn to the latter by muscular exertion, 

 thereby interfering with its due expansion, and 

 their own freedom, are at full liberty. 



Let us now turn to the analogous parts of 

 the lower animals, — and first let us take the 

 ape tribe, which are called quadrumanous, that 

 is, four-handed, because all four extremities 

 are constructed as graspers. In man alone, of 

 all the mammalia, is the erect bipedous attitude 

 easy and natural. The structure of the spine 

 and trunk, the bony and muscular develop- 

 ment of the lower limbs, and the balance of 

 the skull on the top of the vertebral column, 

 combine to necessitate such an attitude. In 

 the ape tribe, animals for the most part of 

 arboreal habits, their progression on the ground 

 is on all fours, and their attitude is crouching, 

 or more or less diagonal — a posture inter- 

 mediate between the upright and horizontal. 

 The lower part of the trunk is contracted and 

 slender — there is no development of the 

 haunch bones and their muscles — the thighs 

 are meagre and ordinarily drawn up to the 

 body, with the knees acutely bent, a position 

 favourable for sudden and vigorous leaps, which 

 these animals execute with great address. 



B 



