THE EXTERNAL FOBM OF ANTHROPOID APES. 15 



are present. In the gorilla these consist of a rather 

 scanty growth of coal-black bristles, about 40 mm. 

 in length. Beneath the projecting supra-orbital 

 arches are the eyes, opening with somewhat narrow 

 slits, and with lids which display many and deep 

 longitudinal folds. The upper lid is set with longer 

 and thicker eyelashes than the lower. The dark eyes 

 glow between,the lids with a ferocious expression. 



The bridge of the nose rises gradually outwards 

 from between the inner corners of the eyes, and is 

 keel-shaped in the centre. This part of the head 

 is from 70 to 80 mm. in length, longer and narrower 

 in one individual, shorter and wider in another. 

 The skin in this region is covered with a network 

 of wrinkles of varying size. The end of the nose 

 and the nostrils are high, conical, and very wide at 

 the base. This part of the nose, attached to the 

 very projecting forehead, has the effect of an alto- 

 gether snout-like muzzle. It is intersected by a 

 central longitudinal furrow, which divides the whole 

 tip of the nose into two symmetrical halves. This 

 furrow is more strongly marked in the case of 

 adult animals than in the young. The aperture 

 of the nostrils is large and triangular, with the 

 cartilaginous point turned upwards, and the edges 

 applied to the bridge of the nose and to the cheeks 

 have a somewhat retreating appearance. The lateral 

 margins of this part of the nostril take an arched 

 form, first diverging in different directions, then 

 gradually converging again towards the upper lip. 

 The lip is short, and this, combined with the large 

 nose, gives a certain resemblance to the mouth of 



