EXTERNAL FORM OF THE MAN-LIKE APES. 743 



of the foot is thick and horny, but provided with a series of papillae. 

 The whole skin of an aged animal is of a deep black color, somewhat 

 glossy, and covered' with intersecting wrinkles. 



The young male gorilla does not essentially differ from the old 

 male in its general and external appearance. Its skull is, however, 

 without the crest which characterizes the latter animal, and is still of 

 a rounded form in the region of the crown and occiput. At this age 

 the head is not so high at the back and on the top as in aged males. 

 The orbits are less prominent, the general aspect of the face is not so 

 decidedly prognathous, and the bridge of the nose is shorter. The 

 lines of the body in the young male are softer and less exaggerated, 

 and the expression of the face is less ferocious than in an aged male. 

 The horny callosities on the hands and feet are altogether wanting or 

 only faintly indicated, and the hands, fingers, and toes have not 

 arrived at the ]50werful development which we observe in the older 

 animal. 



Considerable differences may be observed in the whole structure 

 of the adult female gorilla. The animals of this sex are smaller and 

 weaker than males of the same age. The skull of the female is smaller 

 and more rounded than that of the male, and the great bony crests are 

 also absent. The orbits are less prominent, and a front view of the 

 head gives the impression of a trapezoidal form. The coronal arch 

 rises above this trapezoid. In the male, on the contrary, the crown 

 seems to lengthen above and behind into a pyramidal form. In the 

 aged female the bridge of the nose is generally shorter than in the 

 aged male ; but even in this particular there is great variation in dif- 

 ferent individuals. Sometimes the bridge of the nose in a female is 

 much depressed, and then the interval between the orbits and the end 

 of the nose is shorter : I intentionally avoid the terra tip of the nose, 

 on account of the blunted form of this organ. Even when the bridge 

 of the nose is more prominent, the interval between its end and the 

 orbits is sometimes very short. 



The aged female gorilla usually has wider cheeks, a smaller nose, 

 and a higher upper lip. This last peculiarity is shown in the correct 

 and well-stuffed specimens in the museums at Paris and Liibeck. Al- 

 though in the process of drying the skin of the nose may have shrunk 

 a little, yet there is still room for the upper lip, provided with folds 

 which are either vertical and parallel or diverge like a fan. Owen and 

 Miitzel* have given satisfactory illustrations of these parts. In the 

 aged female the shape of the neck is not, as in the aged male, strong 

 and bulging, so as to resemble a cowl. Yet it is enlarged in conform- 

 ity with the not inconsiderable development of the spinous processes 

 of the cervical vertebrae, and with that of the powerful cervical mus- 

 cles. Even in a young male, of the age of the specimen which was 

 kept in the Berlin Aquarium, between July, 1876, and November, 1877, 

 * Owen, " Memoir," etc., plate ii ; Brchtn, " Thierleben," vol. i, p. 56. 



