352 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
mixed with black, especially on the limbs; breast pale yellowish, varying 
to bright fulvous. 
A specimen from Tehuantepec (No. 9430), collected December 3, is the 
most highly-colored of any in the collection, and agrees perfectly with Wag- 
ner’s description of his variety flavigu/aris. In this, the color above is bright 
yellowish-brown, strongly variegated with black. The neck in front and the 
breast are strongly yellowish-brown, which color extends forward on either 
side of the throat and along the sides of the body. The rest of the lower 
parts are pure white; the legs are of a pure, rather dark, gray, which color, 
rather more mixed with black, extends over the thighs and the sides of the 
rump. The fur is everywhere very short and rather harsh, as compared with 
winter specimens of var. ¢exianus; the pelage of the legs is especially short, 
so that these parts look very small and slender. 
Summer specimens from Southern Texas (Nos. 252, 241, 134, etc.) 
present the same general features of short, rather harsh, pelage, very scantily- 
clothed legs and feet, and brighter and purer colors; but the fulvous tint, 
especially over the fore neck and breast, is of a much more brownish cast. 
A specimen from Orizaba, Mexico, quite closely resembles, in the color of 
the dorsal surface, the specimens from Texas, but the brownish tint of the 
breast and sides of the body ig nearly obsolete, the whole lower surface 
of the body being almost uniformly pure white. A striking feature in this 
specimen, remarkable for the general lightness of its colors, is the terminal 
white patch on the ears. 
Considering the varieties in their co-specific relationship, we find that 
the Texan and Mexican specimens are much more strongly colored, especially 
in respect to the fulvous tint, than specimens of the more northern type, 
while the palest specimens come from Arizona and Utah. A specimen from 
Boisé River, Oregon, is varied with black and gray above, with only a very 
faint tinge of brownish on the limbs, sides, and breast. 
The black at the tip of the ear varies from a patch an inch or more in 
length to a narrow terminal bordering, and is sometimes wholly obsolete. 
It is narrower in Texas specimens than in those from Arizona and Utah, 
existing in some of the former only as a very narrow border, while in the 
specimens from Mexico it is wholly absent, being replaced in one by white 
and in the other by fulvous. 
The extremes in respect to variation in color, as indicated in the varietal 
diagnoses, present very wide differences, but there are so many intervening 
