Chap. VII. 
THE RACES 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 anirtials, 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 days. These Pediculi 
s ‘Transact. R. Soc. of Edinburgh/ vol. xxii. 1861, p. 567. 
