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MONOOUAl'llS OF NOllTII AMElllCAN UODBNTIA. 



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wliilo tlic Pacific-coast forcst-siK-cimciis Imvo a ratlicr coarser and harsher fur. 

 This character, too, 1ms entered into a specific diagnosis; yet, allhougli 

 the point cannot be reduced to figures and proven mathematically, we declare 

 tiiat it is iinpossibh; t(t draw a dividing line between these conditions. 



The under parts of this animal arc white— usually snowy-white in Unitcil 

 States prairie skins, and dull soiled white, or even ashy-white, in Arctic und 

 Pacific coast specimens. The remark just made applies here with undimin- 

 ished tbrce. 



The upper parts correspond with the under. In the prairie skins, the 

 color is very bright ; a rich liiwn or lutoous-brown, lined with black on the 

 back. In all the Arctic ones, and Ijkewise in the Pacific-coast ones, the shades 

 arc much darker, more inclining to ordinary rat-color, but always with more 

 or less of a clayey-brown or rusty-gray. Young animals from these regions, 

 respectively, are dull pale gray and deep slate-gray. One specimen (No 

 3318), apparently a sickly or otherwise abnormal example, is rusty-red 

 underneath. But all these various shades of color are so inextricably mixed, 

 that it is out of the question to base a specific character upon them. 



It is interesting to observe, in this connection, that the tail does not seem 

 to share this variation in color. In the tawniest jjrairic skins, as in the rest, 

 the tail is ashy-gray above, white below. Sometimes, indeed, the tail is paler, 

 or even a little browner, than in other cases; but it is essentially gray in all 

 cases — discolor with the back in the rusty skius, concolor with the back in 

 the dark ones. 



We are i)lcased to notice in this animal the strongest possible cbnfirma- 

 tion of the views reached in our discussion of various supposed species of 

 Hesppromi/,1, concerning geographical strains. We solve the whole Neotoma 

 question in a nutshell, when we say that it is parallel with the case of Hes- 

 jieromys "austerus" as far as dark color and length of tail of N. "occidentalis" 

 are concerned; and with the "uebrascensis" style of "sonoriensis" as far as 

 color is concerned. We may, in a rude way, throw the Neotoma skins before 

 us into three heaps : first, the Arctic ones, thickly clad, short-tailed, dark-col- 

 ored ; secondly, the United States prairie ones, thinly clad, short-tailed, bright- 

 colored; thirdly, the Pacific-coast ones, medium clad, long-tailed, dark-colored. 

 If there be more than one " species", there certainly are three ; and granting, for 

 a moment, that there are two, the Arctic ones, of course the true N. drum- 

 mondii, look much more like the Pacific-coast ones than they do like the 



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