DESCENT OF MAX FROM SOME LOWER FORM. 169 



suggested by the case of the rabbits may hold good ; for 

 Welcker finds that short "men incline more to brachy- 

 cephaly, and tall men to dolichocephaly " ; and tall men 

 may be compared with the larger and longer-bodied rab- 

 bits, all of which have elongated skulls, or are dolicho- 

 cephalic. 



From these several facts we can understand, to a cer- 

 tain 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 comparison with the lower animals. 



NAKEDNESS OF THE SKIX. 



D . Another most conspicuous difference be- 



of Man, tween man and the lower animals is the 

 page 56. nakedness of the skin. Whales and porpoises 

 (Cetacea), dugongs (Sirenia), and the hippopotamus 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 

 certain extinct species, which formerly lived under an 

 Arctic climate, were covered with long wool or hair, it 

 would almost 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 

 iufer that man became divested of hair from having abo- 

 riginally inhabited some tropical land ? That the hair 

 is chiefly retained in the male sex on the chest and face, 



