112 NORTH AMERICAN MUSTELID^. 



investigation, it may be stated unequivocally that they fail as 

 bases of specific or even varietal separation. Not that the 

 alleged trifling differences do not exist; I can find them all and 

 others besides : but they occur equally in the specimens from 

 all countries, are not in the least correlated with any supposed 

 geoo'raphical limits, and are, in short, an expression merely of 

 the normal individual variability of the animal. As perfect 

 duplicates as I ever examined came from Alaska and Northern 

 Europe respectively: in all those nice points of pelage, shades 

 of color, &c., which the practiced eye recognizes, they are 

 more exactly alike than, for example, several specimens from 

 England and France are among themselves. Every point which 

 has been seized upon to separate an American from the Old 

 World animal is nullified by sufficient series of specimens. 



In seeking either resemblances or differences in the nicer 

 minor points, we must not look at the animals as limited by 

 certain continental areas, nor in any way by longitude : experi- 

 ence proves that this would be useless. A creature of thoroughly 

 and cousi)icuously circumpolar distribution, extending probably 

 as near the pole as any land Mammal, it is modified, when 

 changed at all, by latitude, as expressed in the climate to which 

 it is subjected, state of its food-supply, &c. These points are 

 thoroughly understood in the commercial world by those whose 

 wits are sharpened by their pecuniary interests; and it is 

 surprising that some naturalists have failed to appreciate them. 



The existence in North America of the true Ermine being 

 established, there yet remains the question whether there be 

 not also in this country other species of the same type, for we 

 must not hastily assume that, because we have the true Er- 

 mine, all our other Stoats must be identical with it. 



Throwing out of consideration the quite different P. Jongi- 

 cauda, three species have of late years been currently recog- 

 nized. These are the P. novehoracemis of De Kay, P. richard' 

 soni of Bonaparte {=zagiUs Aud. and Bach.), and P. cicognani 

 of Bonaparte {=fuscus A. and B.). Of the first-named it may 

 be said, simply, that it is based upon the ordinary United States 

 animal, of dimensions exactly corresponding to an average 

 English specimen, for instance, and not otherwise different. 

 This may be accepted as a convenient standard of comparison 

 for the ordinary United States animal, identical with that from 

 corresponding latitudes in the Old World. The P. richardsoni 

 of Bonaparte was originally a mere presumptive attempt to 



