134 ANTHROPOID APES, 



well as the examination of its dead body, make it 

 clear that the action of the ball and socket is remark- 

 ably free, and this theoretical surmise is contradicted 

 by the perfection of the natural mechanism. 



The excessive curvature of the forearm which we 

 notice in the gorilla and the chimpanzee in their 

 natural condition is rare in man, and when it does 

 occur it must be regarded as an abnormal and 

 pathological phenomenon. 



The orang-utan always displays a ninth carpal' 

 bone, corresponding to de Blainville's os intermedium 

 and Gegenbaur's os centrale carpi. In a very young 

 animal I found that this small bone was furnished 

 with a peculiar point of ossification. The bony 

 structure of the wrist is developed in the following 

 succession : — First, the os magnum and unciform 

 bones ; second, the scaphoid bone ; third, the 

 trapezium ; fourth, the semi-lunar bone ; fifth, the 

 cuneiform bone ; sixth, os centrale carpi ; seventh, 

 the trapezoid bone. The pisiform bone and the 

 sesamoid bone, between the trapezium and the sca- 

 phoid bone, of which we shall speak presently in 

 their relation to the muscular system, are at first 

 simply cartilaginous. 



Up to this time my search for this ninth carpal 

 bone in the gorilla and the chimpanzee has been fruit- 

 less, since its occurrence is only exceptional. In the 

 gibbon it is plainly inserted between the scaphoid, 

 semi-lunar, trapezoid, and os magnwm. Gegenbaur 

 considers the os centrale to be a true constituent of 

 the wrist, dating from an earlier condition, but he 

 has nothing to suggest as to its subsequent survival. 



