Homo erectus 



\-r> 



656 

 III 



404 



500 



X 



Homo habilis 

 N = 3 



Australopithecus 

 africanus 



N = 6 



A. robustus 



530 



X 



A. boisei 



Gorilla 



N = l 



N = 653 



ill 2 



303.8 



250 



-+- 



-t- 



350 450 550 



-t- 



Orang-utan 



Chimpanzee 



N = 144 



-4 



650 750 850 

 Capacity in c.c. 



-t- 



+ 



-+- 



-4- 



050 1050 U50 1250 



Figure 13: The cranial capacities of available samples of fossil hominids 

 compared with those of extant great apes. The sample mean is indicated 

 in each instance by a narrow vertical line. No attempt has been made 

 in this diagram to separate the sample for each hominoid into male and 

 female subsamples. 



centimeters and, then, in terms of numbers of S.D.s departure from the 

 sample mean. None of these data, however, has been given. Subsequently, 

 he returned to this theme: 



... it seems clear that variation in brain size in modern man and also the Afri- 

 can great apes is such that the observed upper limits exceed appreciably, espe- 

 cially in man, the traditional limit set by three times the standard deviation above 

 the mean calculated from samples of substantial size. [Robinson 1968, p. 171] 



& 30 



