THE EXTERNAL FORM OF ANTHROPOID APES. 17 



view of the head, and indeed of the whole animal, 

 presents a strongly projecting contour, an impres- 

 sion which is strengthened by the puffed cheeks, 

 with their lateral pads of fat. The lower jaw, with 

 its scarcely indicated chin, retreats in the centre and 

 dwindles into a triangular form. This contour is 

 characteristic of the species. The whole skin of the 

 face is glossy? set with few hairs, and of a deep 

 black colour. 



Fig. 2.— Ear of a male adult gorilla. 



The ear (Fig. 2) averages 60 mm. in length, and 

 from 36 to 40 mm. in width. It seems to be fastened 

 to the head by the back and upper part, is generally 

 of an oval shape, and furnished with a strongly 

 marked helix. The helix varies in width in different 

 individuals, and often terminates on its inner edge 

 in the projecting peaked excrescence described by 

 Darwin, of which I shall have more to say presently. 

 The anti-helix, tragus, and anti-tragus, and the cleft 



