6 3 8 



MAN 



xxiv. 8 



the neck. The enlargement of the brain has been in the occipital and 

 especially in the frontal region (p. 633), giving a high forehead and the 

 characteristic upright face. At the same time the jaws have receded, so 

 that the human tooth-row is unusually short. Moreover, the dental 



Pithecanthropus 



H. sapiens 



Fig. 413. Skulls of apes and man. The face and back of jaw of 



* 'Pithecanthropus has been restored. (Partly after Romer, 



Vertebrate Paleontology, University of Chicago Press.) 



arcade is characteristically rounded in front, that of apes is U-shaped, 

 with large canines at the bend (Fig. 409). In man the canines are small 

 and incisiform; the first lower premolar is bicuspid, like the rest and 

 not sectorial as in other catarrhines. The molars show a characteristic 

 pattern that may be regarded as based on four cusps above and five 

 below. The cusps are arranged roughly as a rectangle, so that the 

 grooves between them make a + as compared with the Y patterns 

 typical of the dryopithecine molar (Fig. 414). Thus the protoconid 

 meets the entoconid in the human but not in the earlier type. However, 



