404 THE ANATOMY OF VERTEBRATED ANIMALS. 



their span, when outstretched, being nearly double the height 

 of the animal. The brachium and the antibrachium are equal 

 in length. The long and narrow pes is longer than the equal- 

 ly narrow manus, and the sole cannot be placed flat upon the 

 ground, but the animal rests upon the outer edge of the foot 

 when it assumes the erect posture. This posture, however, is 

 quite unnatural, and the Orangs cannot run as the Gibbons 

 do, but swing themselves along upon their long arms, as it 

 were upon crutches. 



The pollex and the hallux are both short, the latter remark- 

 ably so ; and the hallux is not uncommonly devoid of a nail. 

 The palmar and plantar aspects of the dig-its are naturally con- 

 cave, and they cannot be completely straightened. 



The Chimjoanzee attains a stature somew^hat greater than 

 that of the average Orang. The span of the arms is about 

 half as much again as the height. The antibrachium is about 

 as long as the brachium. The manus is equal to, or a little 

 longer than, the pes ; and these parts of the limbs are not so 

 elongated, or so curved, as the corresponding parts of the 

 Orang. The sole can be readily placed flat upon the ground, 

 and the Chimpanzee easily stands or runs erect. But his fa- 

 vorite attitude is leaning forward and supporting himself on 

 the knuckles of the manus. Both the hallux and the pollex 

 are well developed and possess nails. 



The Gorilla exceeds five feet in height and may reach five 

 feet six inches. The span is to the height as about three to 

 two. The brachium is much longer than the antibrachium. 

 The pes is longer than the manus, and both are much 

 broader than in the other Antliropomorpha. In consequence 

 of this circumstance and of the greater development of the 

 heel, the erect posture is easily maintained, but the ordinary 

 attitude is the same as that assumed by the Chimpanzee. The 

 hallux and the pollex have well-developed nails. The basal 

 phalanges of the three middle digits of the foot are bound 

 together by the integument. 



With respect to the skeleton in the Antliropomorpha^ the 

 Gibbons have the spinal column nearly straight, with a very 

 open vertebro-sacral angle. In the Orangs the dorso-lumbar 

 vetebrse form a curve, which is nearly as much concave for- 

 ward as in a new-born child. In the Chimpanzee the spinal 

 column begins to exhibit the curvatures which are character- 

 istic of the adult human subject; and these are still more 

 marked in the Gorilla. 



The spinous process of the second cervical vertebra is 



