78 ANTHROPOID APES. 



The coronal part and the squamous occipital parts 

 are arched ; the upper jaw is smaller, and the lower 

 jaw is also less massive, than in the male animal. 

 In very young animals the predominance of the 

 stronfflv arched cranium over the countenance is 

 apparent, and the increase of size in the latter 

 occurs gradually (Fig. 23). 



The anterior nares are narrow at the top, and 

 wide at their base. They are more decidedly pear- 

 shaped {Apertura pyriformis) than those of the gorilla 

 and chimpanzee. In the latter animals these aper- 

 tures are generally wider and more uniformly rounded. 

 Bischoff justly observes that the bony part below 

 the orbits, which in the gorilla is wide above, 

 tapering away in the lower part of the face, is 

 narrower and more vertical in the orang. The 

 nasal bones of the orang are high and of moderate 

 width. Briihl mentions the styloid process of the 

 orang's skull, which is, however, somewhat abortive 

 when we compare it with that of the human skull. 

 It has its origin in a tolerably deep groove. On the 

 other hand, Briihl, as we have already observed, can 

 find no trace of the styloid process in the skulls of 

 the gorilla and the chimpanzee ! * 



There are many large-celled bony cavities in the 

 orang's skull. These may be observed in the greater 

 wings and pterygoid processes of the sphenoid bone, 

 in the mastoid and squamous parts of the temporal 

 bones, in the lachrymal bones, in the body, and in 

 the condyles of the occipital bone, and in the zygo- 

 matic arch. The larger fore-cells on the squamous 



* JBrnlil, Zur Kenntniss des Orangkoiifes, pp. 2, 3. 



