140 



LECTUEE VI. 



Camper's facial angle varies in man from 70 degrees to 

 85 degrees ; and there is probably no instance of a normal 

 human skull knoVn where it is as low as 64 degrees. In the 

 Negro skull here depicted the angle amounts to 67 degrees ; 

 and, according to Geoffroy St. Hilaire, the skulls of the Makoias 

 or Namakas, a South African tribe, sent to the Paris Museum 

 by Delalande, have a facial angle of only 64 degrees ; whilst it 

 decreases in the adult chimpanzee to 35 degrees, in the orang 

 to 30 degrees ; though when these animals are young, and the 

 jaws undeveloped, it frequently reaches 60 degrees. On the 

 other hand a small American ape, the saimiri {calUthrix sciurea), 

 as regards organisation, is far more remote from man, but very 

 human-like in behaviour in some respects (it weeps readily, 

 for instance) ; has a facial angle of 65 to 66 degrees ; so that it 

 completely fills up the gap. Equally decided are the differences 



Fig. 43. Skull of an aged Chimpanzee, top view. 



observed in the development of the jaws. The temporal 

 muscles which raise the jaws must be stronger in the apes, 

 inasmuch as they have to move a longer lever, independently 

 of the greater development of the jaws in width. Hence the 



