MANNER OF DEVELOPMENT. 63 



even so trifling a cause as the lopping forward of one ear 

 drags forward almost every bone of the skull on that side; 

 so that the bones on the opposite side no longer strictly 

 correspond. Lastly, if any animal were to increase or 

 diminish much in general size, without any change in its 

 mental powers, or if the mental 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 cer- 

 tainly be altered. I infer this from my observations on 

 domestic rabbits, some kinds of which have become ver}^ 

 much larger than the wild animal, while others have re- 

 tained nearly the same size, but in both cases the brain has 

 been much reduced relatively to the size of the body. Xow 

 I was at first much surprised on 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 3.15 and the 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;"t 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 com- 

 parison with the lower animals. 



Another most conspicuous difference 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 in- 

 habit the colder regions are protected by a thick layer of 

 blubber, serving the same purposes as the fur of seals and 



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

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



f Quoted by SchaaJlhauseu, in " Anthropolog. Review," Oct., 1868, 

 p. 419. 



