190 SECTIONAL ADDRESSES. 



and the brows are then usually less outstanding as elements distinct from 

 the brain-case. In other cases again the temporal muscles seem to exercise 

 still less influence on the skull, and growth is not so predominantly a growth 

 along the coronal suture ; here the head is less narrow, the brow-ridges 

 are generally weaker, and, especially in women who have little growth of 

 brow-ridges, the forehead may even bulge forward to some extent above 

 the brows. 



Lest too much importance be attached to the influence of the temporal 

 muscles upon the skull-form attained as growth proceeded, it is well to 

 remember that the face was still strongly developed in most early examples 

 of modern man, and that to balance this the head must project backwards 

 a good deal ; therefore growth in length would be marked in those forms 

 which had a weighty development forwards. This occurred in most cases, 

 whether the skull was very narrow and high or less narrow and lower. 

 This growth in length leading to backward projection resulted, as has been 

 said, chiefly from growth of the front part. 



In trying to understand the variations in form of early Neanthropic 

 men's skulls as essentially growth-differences, it is well to remember that 

 the man of Neanderthal type from La Chapelle aux Saints had a cranial 

 index in the neighbourhood of 80 if the brow-ridges be excluded in taking 

 the length. The relation of breadth to length in the Piltdown skull was 

 about 79 per cent., and most of the apes are brachycephalic (apart from 

 the brow-ridges), though H. A. Harris has recently shown that some 

 gorillas are dolichocephalic* 



It is thus possible to think that, with the growth changes involved when 

 there evolved men of the types found in Aurignacian and Solutrean times 

 in Europe, some individuals responded with little change of cranial index 

 and became what are often called mesaticephals or sub-brachycephals. 

 Others responded with a lesser or greater degree of growth in relative 

 length, not in absolute length be it noted. The skulls with very low 

 cranial index and great height so characteristic for the Solutrean, and to 

 some extent for the Aurignacian phase of culture, are thus held to be an 

 early specialisation among men of modern type, and this view is contra- 

 distinguished from that which has been suggested from time to time, 

 and which supposes that dolichocephaly was the one primitive condition 

 in men of modern type, and that brachycephaly somehow evolved from it. 



When the types of living men are studied, it becomes evident that the 

 heads which have a very low index have a distribution which includes the 

 following features : — 



s 



(a) Many of their locations are peripheral, as though they had been 

 pushed out to the very edges. 



(b) Some of their peripheral locations, and many of those which are 

 not peripheral, are in regions of difficulty which are typically 

 refuges of old types. 



It is unreservedly recognised that this does not account for all the 

 facts. There are, for example, types — e.g. in S.E. Australia — with low 

 indices and heavy brow-ridges, but the head there is generally low, not 

 high, as would be anticipated from what has been urged here. I think 



* ' Endocranial Form of Gorilla Skulls,' Amer. Journ. Phys. Anthr., 1926, p. 167. 



