[hill-tout] PHYLOGENY OF MAN 79 



similarities between the two types. They do not and cannot show 

 us the phases through which our early ancestors passed in their 

 upward course toward humanity, but rather the degrees of differen- 

 tiation undergone by the anthropoid apes after their separation from 

 the common parental stem. However much man has changed in 

 his body and limbs from his Simian ancestors, all lines of evidence go 

 to show that he has changed relatively little in respect to his cranial 

 characters; while it is in these aspects in particular that the apes 

 have changed most, and less in the general characters of their bodies 

 and limbs. In other words, the differentiation of man and the an- 

 thropoids has followed wholly different lines. 



To discover and trace the features they once had in common, 

 we must direct our attention rather to the skulls of the young anthro- 

 poids before they have undergone the differentiations characteristic 

 of the skulls of the mature species; and when we do this we learn not 

 only how great are the changes the anthropoids have passed through 

 in the course of ages, but at the same time how very near they once 

 were in respect to their cranial characters to the type we now regard 

 as the human one. 



A comparative and critical examination of the skulls of the young 

 anthropoids brings out many striking similarities between them and 

 the typical skulls of man, which are wholly wanting in the more 

 highly-specialised skulls of the mature apes. Keith has called atten- 

 tion, for example, to the fact that a characteristic of anthropoid 

 skulls is the more forward position of the highest point in the vault 

 when compared with the same point in the vault of a typical human 

 skull. This point in the mature anthropoid skulls is at or close to 

 the bregma, the junction of the coronal and sagittal sutures. In the 

 human skull it is about two inches behind the bregma. Thus in 

 Figure 8 where the skulls of the Galley Hill man. La Chapelle man 

 and those of Eoanthropus and Pithecanthropus are compared, it 

 will be seen that in this respect Pithecanthropus was truly ape-like 

 and Eoanthropus truly man-like. In the skulls of the young anthro- 

 poids which the writer has had opportunity of examining this point 

 of maximum height would seem to vary with the age of the skull, 

 the younger the skull, the farther back is the maximum point of 

 height. It also varies with the genus of ape, that of the chimpanzee 

 having the highest point farthest back from the bregma. It seems 

 clear from this that the shape and contour of the skulls of the mature 

 anthropoids have beeft modified by the development of the excessive 

 musculature which characterizes them. 



