THE DESCENT OR ORIGIN OF MAN 261 



mhospitabj'e shores; the Botocudos of Brazil wander about 

 the hot forests of the interior and live chiefly on vegetable 

 productions ; yet these tribes resemble each other so closely 

 that the Puegians on board the "Beagle" were mistaken by 

 some Brazilians for Botocudos. The Botocudos again, as' 

 well as the other inhabitants of tropical America, are wholly 

 difEerent from the Negroes who inhabit the opposite shores 

 of the Atlantic, are exposed to a nearly similar climate, and 

 follow nearly the same habits of life. 



Nor can the diflEerences between the races of man be 

 accounted for by the inherited effects of the increased 

 or decreased use of parts, except to a quite insignificant 

 degree. Men who habitually live in canoes may have their 

 legs somewhat stunted ; those who inhabit lofty regions may 

 have their chests enlarged; and those who constantly use 

 certain sense-organs may have the cavities in which they 

 are lodged sohaewhat increased in size, and their features 

 consequently a little modified. With civilized nations, the 

 reduced size of the jaws from lessened use — the habitual 



/ play of different muscles serving to express different emo- 



/ tions — and the increased size of the brain from greater intel- 

 ^ I lectual activity, have together produced a considerable effect 



\)n their general appearance when compared with savages."? 



Increased bodily stature, without any corresponding increase ~) 



( in the size of the brain, may (judging from the previously ) 



> adduced case of rabbits) have given to some races an elon- 

 gated skull of the dolichocephalic type. 



Lastly, the little-understood principle of correlated devel- 

 opment has sometimes come into action, as in the case of 

 great muscular development and strongly projecting supra- 

 orbital ridges. The color of the skin and hair are plainly 

 correlated, as is the texture of the hair with its color in the 

 Mandans of North America." The color also of the skin, 



"' See Prof. Schaaffhausen, translat. in "Anthropological Review," Oct. 

 1868, p. 429. 



^ Mr. Cattin states ("N. American Indians," 3d edit., 1842, vol. i. p. 49) 

 that in the whole tribe of the Mandans, about one in ten or twelve of the 

 members, of all ages and both sexes, hjive bright silvery gray hair, which is 



.v-^ 



