﻿lxvi 



PKOCEEDLKGS OF THE GEOLOGICAL SOCIETY. [May I9IO, 



broad ascending branches at once distinguish it, even to the un- 

 instructed eye, from that of existing* men ; but it is at the anterior 

 extremity that its simian characters are most pronounced. The 

 chin is entirely absent, and the profile is a simple, retreating, gentle 

 curve, similar to that presented by the lower jaw of a chimpanzee or 

 gorilla. In the illustration (fig. 3) the profiles of this region as it 



Tig. 3. — Projections of the Mauer jaw (thick continuous line), the 

 jaw of an Australian aborigine (thin continuous line), and the 

 jaw of a chimpanzee (broken line), superposed on the alveolar 

 line. ( X f.) 



occurs in the Australian, the chimpanzee, and the Heidelberg jaw 

 are superposed on a common base, provided by the alveolar plane, 

 and it will be seen on inspection that the Heidelberg profile stands 

 almost midway between the other two. The inner or posterior 

 face of the anterior extremity is no less simian than the outer ; 

 the surface of the alveolar region slopes downwards more gently 

 than in existing races, but more steeply than in the chimpanzee ; 

 the supramarginal sinus is more sharply expressed than in 

 existing races, and forcibly recalls the corresponding region in 

 the chimpanzee (fig. 4, p. lxvii). Just below it is the region 

 where, in modern Man, we should expect to find the genio-glossal 



