XXIV. 11-12 



AUSTRALOPITHECINAE 



643 



Miocene stock as the apes. Some hold, however, that the human line 

 has been distinct for a much longer period, perhaps even back to a 

 separate tarsioid ancestor in the Eocene. 



A survey of the evidence about the affinities of man and apes will 

 probably lead the unprejudiced to the conclusion that although we do 

 not know enough to be certain, the human stock probably diverged 

 from that of the apes in early Miocene times, perhaps from a form like 

 *Proco?isul, before the brachiating habit had become fully developed. 

 Fig. 416 shows the possible relationship based on this hypothesis, but 



Fig. 417. Skull of Paranthropus. (From a cast.) 



we shall remain uncertain of the exact course of our descent until 

 Pliocene and Miocene fossils that could have been our ancestors are 

 found. 



12. The Australopithecinae 



A series of fossils found in Africa shows a curious combination of 

 the characters of men and apes. The specimens occur in lime deposits 

 probably of early Pleistocene date. Tools occur associated with them 

 but the cranial capacity was between 500 and 750 c.c, hardly greater 

 than in living apes. Several types occur and it is not agreed whether 

 all should be included in the single genus * Australopithecus. The first 

 skull found, in 1924, is that of a young individual, whose rather 

 prognathous jaws and low cranium have an ape-like appearance, 

 though the brow ridges and crests are slight (Fig. 413). Later finds 

 include a different type (* Paranthropus) with marked brow ridges and 

 sagittal and occipital crests (Fig. 417). Evidently the muscles of 



