THE DESCENT OR ORZGlN OF MAN 83 



large domestic kind, the former was 3.15 and tlie latter 4.3 

 inches in length. " One of the most marked distinctions in 

 different races of men is that the skull in some is elongated, 

 and in others rounded; and here the explanation suggested 

 by the case of the rabbits may hold good; for Welcker finds 

 that "short men incline more to brachycephaly, and tall men 

 to dolichocephaly' ' ;°° and tall men may be compared with the 

 larger and longer-bodied rabbits, all of which have elongated 

 skulls, or are dolichocephalic. 



From these several facts we can understand, to a certain 

 extent, the means by which the great size and more or less 

 rounded form of the skull have been acquired by man ; and 

 these are characters eminently distinctive of him in compari- 

 son with the lower animals. 



Another most conspicuous difiEerence between man and 

 the lower animals is the nakedness of his skin. Whales 

 and porpoises (Cetacea), dugongs (Sirenia), and the hippo- 

 potamus are naked; and this may be advantageous to them 

 for gliding through the water; nor would it be injurious to 

 them from the loss of warmth, as the species which inhabit 

 the colder regions are protected by a thick layer of blubber, 

 serving the same purpose as the fur of seals and otters. 

 Elephants and rhinoceroses are almost hairless; and as cer- 

 tain extinct species, which formerly lived under an Arctic 

 climate, were covered with long wool or hair, it would al- 

 most appear as if the existing species of both genera had lost 

 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" than those on the 

 lowlands. May we then infer that man became divested of 

 hair from having aboriginally inhabited some tropical land ? 

 That the hair is chiefly retained in the male sex on the chest 

 and face, and in both sexes at the junction of all four limbs 



8' "Variation of Animals," etc., vol. i. p. 117, on the elongation of the 

 skuU; p. 119, on the efEect of the lopping of one ear. 



»*' Quoted by SchaafEhausen, in "Anthropolog. Eeview," Oct., 1868, p. 419. 

 8' Owen, "Anatomy of Vertebrates, " vol. iii. p. 619. 



