18 ANTHROPOID APES. 



which lies between these two latter parts (incisura 

 inter tragiea) are generally fully developed ; the 

 lobule is more rarely present. Individual variations 

 in the special structure of these parts may frequently 

 be observed. 



The strong trapezoid muscles are prominent on 

 the neck, and when the head is stretched they 

 stand out like pillars on the sides of the neck. 

 Owing to the great development of the spinous pro- 

 cesses of the cervical vertebrae and of the muscles 

 attached to them, and to the occipital bones of the 

 skull, the neck is very powerful, almost like that of 

 a bull. The shoulders are remarkable for their 

 breadth, and the pectoral muscles for their large 

 size. The nipples of the breast, which are not sur- 

 rounded by any visible areolm, stand out in youth, 

 and afterwards assume a horny texture which stiffens 

 into a kind of bone. When one of these animals is 

 gorged with food the navel is still apparent on the 

 tun-shaped, rounded belly, of which the sides fall 

 in when the stomach is empty. 



On the upper and forearms the plastic form of 

 the strongly developed flexor and extensor muscles 

 is very apparent, testifying to the enormous strength 

 of the upper extremities. The hands are large, and 

 very wide, with short, thick fingers. The thumb, 

 of which the extremity takes a conical form, is short, 

 extending little beyond the middle of the second 

 metacarpal bone. The extremities of the other- 

 wise broad fingers are somewhat laterally compressed. 

 The fore-finger is not materially shorter than the 

 middle finger. The third finger is sometimes shorter 



