188 



THE GENESIS OF SPECIES. 



[CHAP. 



and indeed he says, " The nature of the bond of correlation 

 is frequently quite obscure." Now, it is surely more desir- 

 able to make use, if possible, of one conception than to im- 

 agine a number of, to all appearance, separate and inde- 

 pendent " laws of correlation " between different parts of 

 each animal. 



But even some of these alleged laws hardly appear well 

 founded. Thus Mr. Darwin, in support of such a law of 

 concomitant variation as regards hair and teeth, brings for- 

 ward the case of Julia Pastrana, 18 and a man of the Burmese 

 court, and adds : 19 " These cases and those of the hairless 

 dogs forcibly call to mind the fact that the two orders of 

 mammals, namely, the Edentata and Cetacea, which are 

 the most abnormal in their dermal covering, are likewise 



THE AARD-VARK (ORYCTEROPUS). 



the most abnormal either by deficiency or redundacy of 

 teeth." The assertion with regard to these orders is cer- 



18 A remarkable woman exhibited in London a few years ago. 



19 "Animals and Plants under Domestication," vol. ii., p. 328. 



