54.6 % 



Vk- °^ 



563 c.c. 1030 c.c. 



Figure 19: The biparietal partial endocast and the total endocast of Homo 

 erectus peki?ie?isis II from Choukoutien, China. 



estimate, i.e., S.D. = 50 c.c). Both of these values exceed, in number of 

 S.D.s in excess of the mean, the maximum values computed for living 

 hominoids (see Table 7), namely +3.88 and +3.78 for man, +3.89 or 

 + 3.81 for male gorilla, and +3.75 for male and female gorilla. 



In relation to my estimate of the A. africanus mean (494 c.c), the 

 H. habilis excess of 3.93 S.D.s just exceeds the greatest excesses in the list 

 (those of modern man and of gorilla males) but far exceeds those of 

 orangutan and chimpanzee, as well as the limits customarily accepted as 

 indicating a significant difference for a normally distributed variate. Clearly, 

 the type specimen of H. habilis of Olduvai was significantly larger-brained 

 than A. africanus of South Africa.* 



Correcting for the juvenile age of Olduvai Hominid 7. The fore- 

 going discussion, it must be remembered, has been based on a capacity 

 estimated for a juvenile specimen. Should the value be corrected in order 

 to obtain the "adult value" of H. habilis? The dental age of the type 

 specimen is, by modern standards, about twelve years, the second molars 



* Holloway's (1970) calculations likewise show a significant difference between the capacity esti- 

 mated for Old. Horn. 7 (657 c.c.) and that for gracile australopithecines of South Africa. The 

 figure of <ir,- c.c. exceeds by 215 c.c, or g.g6 S.D.. his mean of 442 for the gracile australopithe- 

 cines; if the mean of 450 c.c. is considered, the excess is 207 c.c, or 9.20 S.D.s. 



* 6 8 



