Chap. IV. 
MANNER OF DEVELOPMENT. 
149 
their hairy covering from exposure to heat. This appears 
the more probable, as the elephants in India which live 
on elevated and cool districts are more hairy 77 than those 
on the lowlands. May we then infer that man became 
divested of hair from having aboriginally inhabited some 
tropical land? The fact of the hair being chiefly 
retained in the male sex on the chest and face, and in 
both sexes at the junction of all four limbs with the 
trunk, favours this inference, assuming that the hair was 
lost before man became erect ; lor the parts which now r 
retain most hair would then have been most protected 
from the heat of the sun. The crown of the head, 
however, offers a curious exception, for at all times it 
must have been one of the most exposed parts, yet 
it is thickly clothed with hair. In this respect man 
agrees with the great majority of quadrupeds, which 
generally have their upper and exposed surfaces more 
thickly clothed than the lower surface. Nevertheless, 
the fact that the other members of the order of Pri- 
mates, to which man belongs, although inhabiting vari- 
ous hot regions, are well clothed with hair, generally 
thickest on the upper surface , 78 is strongly opposed 
to the supposition that man became naked through the 
action of the sun. I am inclined to believe, as we 
shall see under sexual selection, that man, or rather 
primarily woman, became divested of hair for orna- 
mental purposes ; and according to this belief it is not 
77 Owen, 1 Anatomy of Vertebrates,’ vol, iii. p. 619. 
78 Isidore Geoffroy St.-Hilaire remarks (‘ Hist. Nat. Generate, ’ tom. 
ii. 1859, p. 215-217) on the head of man being covered with long hair ; 
also on the upper surfaces of monkeys and of other mammals being 
more thickly clothed than the lower surfaces. This has likewise been 
observed by various authors. Prof. P. Gervais (‘Hist. Nat. des Mam- 
miferes,’ tom. i. 1854, p. 28), however, states that in the Gorilla the 
hair is thinner on the back, where it is partly rubbed off, than on the 
lower surface. 
