THE EVOLUTION OF MIND 



of the cerebrum is larger than in inferior mam- 

 mals ; but in these animals, as in the lowest 

 races of men, the frontal extension is but slight, 

 and the forehead is both low and narrow. In 

 civilised man, the anterior portion of the cere- 

 brum is greatly extended both vertically and 

 laterally. As already observed, the most pro- 

 minent physiological feature of human progress 

 has been the growth of the cerebrum. The 

 cranial capacity of an average European exceeds 

 that of the Australians and Bushmen by nearly 

 forty cubic inches ; and the expansion is chiefly 

 in the upper and anterior portions. 



But this parallelism between increased in- 

 telligence and increased size of the cerebrum 

 is complicated by a further parallelism between 

 the amount of intelligence and the irregular 

 creasing and furrowing of the cerebral surface. 

 In the higher mammals both the cerebrum and 

 the cerebellum are convoluted. But the con- 

 volutions do not correspond with any " bumps," 

 real or imaginary, on the external surface of the 

 skull ; they are not symmetrical on opposite 

 sides, like the fancied " organs " of the phreno- 

 logists ; nor indeed, so far as the general brain 

 surface is concerned, do they constitute eleva- 

 tions and depressions at all. The surface of the 

 brain does not resemble a group of hills and 

 valleys, but rather a perfectly smooth table-land 

 cut here and there by very steep and narrow 

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