i6 



SCIENCE PROGRESS. 



Dr. Collignon has plotted the distribution of these 

 indices for the Department of Dordogne alone. We have 

 seen that the northern cantons are what he termed dolicho- 

 cephalic, and the southern are brachycephalic. The length- 

 height index of the former varies between 65 to 68, and of 

 the latter from 70 to 72. Taking the mean at 66 and 70 re- 

 spectively, it follows that the dolichocephals are platy- 

 cephalic and the brachycephals hypsicephalic ; but this 

 platycephaly is a true flattening of the skull, and is not 

 merely due to a lengthening of the cranium, as it is not the 

 most dolichocephalic cantons that are the most platy- 

 cephalic. 



Fig. 5. The Distribution of the 

 Height-Length Index in Dordogne. 



Fig. 6. The Distribution of the 

 Height-Breadth Index in Dordogne. 



70 + Hypsicephalic (shaded) 85 + 



67 - 70 Mesocephalic (blank) 83 - 85 



- 67 Platycephalic (cross-hatched) 81 - 83 

 The oblique band enclosed with a thick line corresponds to the division between 

 the dolichocephals and brachycephals (see fig. 2). 



On the other hand, all the brachycephalic cantons have 

 a height-breadth index of from 8 1 to 84, that is they are, or 

 appear to be, platycephalic and mesocephalic, but their 

 mean is mesocephalic. 



The mixed race who inhabit the zone between the 

 brachycephals and dolichocephals (cephalic index 80-82) is 

 also intermediate with a height-breadth index of 83-85, but 

 the dolichocephals fall into two groups, the one with indices 

 from 85 to Sy are hypsicephalic, the others, like the brachy- 

 cephals, are mesocephalic and platycephalic. 



