80 THE ROYAL SOCIETY OF CANADA 



In the mastoid process we see the same influence at work. This 

 process in the skulls of the young anthropoids of all genera is much 

 more human-like than that in the skulls of the mature apes. In the 

 latter the slightly flattened projecting knob of bone has developed 

 into a thick flange-like plate, and forms part of the occipital platform 

 to which are attached the great neck muscles. In the typical human 

 skull this process is a pyramidal-shaped bony boss or projection. 

 In the young of the anthropoids this process is neither wholly human 

 nor wholly simian, but partly one and partly the other; that is to 

 say, it is an intermediate type. In this respect it closely resembles 

 this feature in the skulls of Neanderthal man, being almost identical 

 with the mastoid process as seen in the Gibraltar woman. 



Taking the skulls of young anthropoids feature by feature, there 

 are so many points in which they resemble the human skull that we 

 are obliged to postulate a common ancestral form for both to ration- 

 ally explain these resemblances. There are differences, of course, 

 and some of them marked, for the young anthropoid not only inherits 

 the features of its remote ancestor, but also those acquired in the 

 course of ages by its more recent ancestors. But the cumulative force 

 of the resemblances impresses the investigator very profoundly; and 

 just as in our comparisons of the mature anthropoids and man, in 

 respect to the structure of their limbs and trunk, we find that one 

 genus approximates more closely to man in this particular and another 

 in that, so it is in the comparison of the cranial and facial characters 

 of the young anthropoids. In the head of one we find this feature 

 is more human-like, in another that. Thus the head of the young 

 chimpanzee in its contours and general characters is the most human- 

 like of all. Its vault rises higher than that of the other genera and 

 the frontal aspect is strikingly like that of a mature human skull 

 on a smaller scale. Its prognathism is not more pronounced than that 

 in the Grimaldi boy. The nasal opening of the gorilla, both in its 

 position and in its form, is more human-like than that of the other 

 young anthropoids; its prognathism is also slight. The young chim- 

 panzee and gorilla both show the nascent bony ridge about the 

 eyes so characteristic of the mature ape; while in the young orang 

 this feature is wholly wanting, the orang in this respect being most 

 human-like, while on the other hand its prognathism is much more 

 pronounced than in either the chimpanzee or the gorilla. 



No one who has made a comparative study of the characters of 

 the skulls of the young anthropoids and of man can doubt that of 

 all the Primates man has changed least in head form and general 

 cranial characters; and that if we would get the clearest conception 



