[hill-tout] PHYLOGENY OF MAN 65 



the ape or even like those of Pithecanthropus as so many students 

 still hold. Regarding the point purely as an abstract question, 

 the contrary is just as likely to be true; that is, instead of finding 

 man becoming more and more ape-like as we go back in time, we 

 shall see the apes becoming more and more man-like; and when we 

 come to consider all the evidence in favor of this view we discover 

 that this is what has really taken place — at least in respect to their 

 cranial characters. It is the anthropoids which have diverged most 

 from the ancestral type — ^not man. They are, as far as their cranial 

 characters are concerned, much more highly specialised and modified 

 than he. Man has kept the ancestral head-form much more closely 

 than the apes as a glance at Figure II in which the skulls of aman, 

 a baby gorilla and a male mature gorilla are contrasted, will plainly 

 show. It is not at all surprising, then, that some of the earliest 

 and less specialised apes should resemble man in his cranial characters 

 more closely than do the highly specialised apes of today. Pithe- 

 canthropus is one of these fossil forms which does this. There were 

 many more anthropoids in earlier times than at present. Some of 

 these we know resembled man more closely than do the anthropoids 

 of today. 



Now if we can discover and learn something about the causes 

 which brought about the changes in the head-forms of the mature 

 anthropoids of today- — ^ changes which differentiate them almost as 

 much from their own young as from man — we shall have gone a long 

 way toward explaining those characters in Neanderthal man that 

 make him so ape-like and dififerentiate him so markedly from the 

 races which preceded and followed him. We get a very good idea 

 of the essential difference between modern man and the men of the 

 Mousterian epoch by a glance at Figure III where Keith has con- 

 trasted the manner in which the heads of the two types of humanity 

 are attached to the body. 



What is it that constitutes the outstanding difference in the 

 heads of most of the living anthropoids and of man? Is it not the 

 excessive musculature of the former and the comparative absence 

 of this feature in the latter? An examination of the skulls of the 

 young of all the anthropoids makes this quite certain. All those 

 bony protuberances, such as the excessive tori or supraorbital arches, 

 and the upstanding crests or median and occipital ridges of the mature 

 apes, especially of the males, which differentiate them almost as much 

 from their own young as from man, all arise from this cause. The 

 very shape of the head has been altered by this excessive musculature, 



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