142 THE DESCENT OF MAN. [P^rt I. 



powers were to be much increased, or diminished, without 

 any great change in the size of the body; the shape of 

 the skull would almost certainly be altered. I infer this 

 from my observations on domestic rabbits, some kinds of 

 which have become very much larger than the wild 

 animal while others have retained nearly the same size, 

 but in both cases the brain has been much reduced rela- 

 tively to the size of the body. Now I was at first much 

 surprised by finding that in all these rabbits the skull had 

 become elongated or dolichocephalic ; for instance, of two 

 skulls of nearly equal breadth, the one from a wild rabbit 

 and the other from a large domestic kind, the former was 

 only 3.15, and the latter 4.3 inches in length. 75 One of 

 the most marked distinctions in different races of man is 

 that the skull in some is elongated, and in others rounded ; 

 and here the explanation suggested by the case of the 

 rabbits may partially hold good ; for Welcker finds that 

 " short men incline more to brachycephaly, and tall men 

 to dolichocophaly ; " " 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 to a certain extent 

 understand the means through which the great size and 

 more or less rounded form of the skull has been acquired 

 by man ; and these are characters eminently distinctive of 

 him in comparison with the lower animals. 



Another most conspicuous difference between man and 

 the lower animals is the nakedness of his skin. Whales 

 and dolphins (Cetacea), dugongs (Sirenia), and the hip- 

 popotamus, are naked ; and this may be advantageous to 

 them for gliding through the water; nor would it be in- 



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

 skull ; p. 119, on the effect of the lopping of one ear. 



" 6 Quoted by Schaaflfhausen, in * Anthropolog. Review,' Oct 18C8J 

 p. 419. 



