EVOLUTION OF THE PRIMATES AND MAN 465 



very thick, and the lower jaw is strikingly similar to that of a 

 chimpanzee, with no chin whatever, and large canine teeth. 

 But the brain-case is dome-shaped and large, with a cubic 

 capacity of about 1170 c.c, and there were no brow-ridges. 

 The latter fact, together with the primitive nature of certain 

 features in the brain, makes it possible to regard Eoanthropus 

 as very close to the line of man's descent, if not his ancestor. 



Pithecanthropus and Eoanthropus date from the latest 

 Pliocene or earliest Pleistocene periods. The remaining 

 fossil men come definitely within the period of the great 

 Ice- Age. 



The most primitive known member of the genus Homo is 

 Homo rhodesiensis, from Broken Hill in Rhodesia. It had a 

 brain- volume of about 1250 c.c, but still lacked any semblance 

 of a forehead. There was no boundary between the nose and 

 the face, and the palate was very big, but its chief specialisation 

 is the development of enormous brow- ridges. The lower jaw 

 is unknown, but it was probably not very different from that 

 of Homo heidelbergensis from Heidelberg, which unfortunately 

 is known only from the lower jaw. It is large and massive, 

 without any chin. The teeth were definitely human, and 

 primitive in that the last molars preserve five cusps, while 

 those of modern man are often reduced to four. 



Incomparably the best known of the fossil men is Homo 

 neanderthalensis, specimens of which have been found from a 

 number of localities in Europe, from Gibraltar to Palestine. 

 In addition to the bones themselves, there is considerable 

 evidence concerning these men from the weapons and tools 

 which they fashioned from flint, and which consequently have 

 been preserved. An indication of the degree of mental develop- 

 ment of these people is obtained from the fact that some of the 

 individuals which have been discovered appear to have been 

 intentionally buried. The brain is very big (about 1350 c.c. 

 on an average), but it preserves numerous primitive features. 

 At the same time, the brow- ridges were large as were also 

 the face, palate, and jaws. There was no chin, and the lower 

 jaw preserves the large attachments for the digastric muscles. 

 The vertebrae and the legs show that the neanderthal man 



2 H 



