Chap. VII. THE EACES OF MAN. 219 



opossum, range from the one into the other, as did 

 formerly some of the gigantic Edentata. The Esqui- 

 maux, like other Arctic animals, extend round the 

 whole polar regions. It should be observed that the 

 mammalian forms which inhabit the several zoological 

 provinces, do not differ from each other in the same 

 degree; so that it can hardly be considered as an 

 anomaly that the Negro differs more, and the American 

 much less, from the other races of man than do the 

 mammals of the same continents from those of the other 

 provinces. Man, it may be added, does not appear to 

 have aboriginally inhabited any oceanic island ; and in 

 this respect he resembles the other members of his class. 

 In determining whether the varieties of the same 

 kind of domestic animal should be ranked as specifically 

 distinct, that is, whether any of them are descended from 

 distinct wild species, every naturalist would lay much 

 stress on the fact, if established, of their external parasites 

 being specifically distinct. All the more stress would be 

 laid on this fact, as it would be an exceptional one, for 

 I am informed by Mr. Denny that the most different 

 kinds of dogs, fowls, and pigeons, in England, are infested 

 by the same species of Pediculi or lice. Now Mr. A. 

 Murray has carefully examined the Pediculi collected in 

 different countries from the different races of man ; 8 

 and he finds that they differ, not only in colour, but 

 in the structure of their claws and limbs. In every 

 case in which numerous specimens were obtained the 

 differences were constant. The surgeon of a whaling 

 ship in the Pacific assured me that^ when the Pediculi, 

 with which some Sandwich Islanders on board swarmed, 

 strayed on to the bodies of the English sailors, they 

 died in the course of three or four clays. These Pediculi 



8 'Transact. E. Soc. of Edinburgh,' vol. xxii. 1861. p. 567. 



