THE FOX AND HIS FUR 205 



the value of the Emperor of Russia's most magni- 

 ficent silver-fox rugs. 



But all the foxes whose pelts are most costly 

 belong to the same family, and the silver fox of 

 Labrador, the choicest of his race, is of the same 

 species as our own fox. In fact, they are mostly 

 variations of the common fox, and of those noted 

 in this chapter only two can really be distinguished by 

 naturalists by well-defined and undoubted characters 

 as belonging to different species. Indeed, Mr. 

 Baird considers that all the American foxes except 

 the grey fox of Virginia, which is perhaps not a true 

 fox, are immigrants from the Old World, for no fossil 

 remains have been discovered in America. They 

 have, with the extraordinary adaptability of the race, 

 varied with the climate, food and surroundings to 

 which they are accustomed, and have adopted the 

 form most suitable to their environment. The fox is, 

 in truth, one support of the theory that species have 

 varied not so much by natural selection, still less by 

 sexual selection, as in correspondence to their en- 

 vironment, and that climate, food, and the conditions 

 of their life have made them what they are. Thus 

 Mr. Allen considers that the much-prized silver and 

 cross foxes are simply cases of melanism among the 

 American foxes to a greater or less extent ; and, 



