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408 



MONOGRAPHS 0¥ NORTH AMERICAN RODENTIA. 



the back and rump. Anteriorly the block-tipped hairs arc fewer, and the 

 dorsal aspect, from the shoulders anteriorly to the nose, is generally more or 

 less strongly tinged with pale yellowish-brown, in strong contrast with the 

 remainder of the dorsal surface. The sides of the body are generally still 

 more strongly washed with ycllowieh-brown, which, over the ventral surface, 

 assumes a much paler tint. In youog specimens, the black-tipped hairs are 

 much fewer, and the pelage generally grayer. The ears, which are well 

 haired on both surfaces, are grayish, tinged more or less with pale yellowish- 

 brown, except anteriorly on the outer surface, where is a large dusky area. 

 Tliey have a well-marked whitish or yellowish-white margin. Anterior sur- 

 face of all the feet yellowish-brown, nearly as bright as on the sides of the 

 body. Soles of the hind feet dusky; palms pale yellowish-brown. Large 

 naked black pads at the base of all the toes. Whiskers numerous, one to 

 two and a half inches long; in some specimens nearly all black, in others 

 only the upper are black, the lower being light-colored to the bases: gener- 

 ally a part have the basal portion black, with the apical half or two-thirds 

 yellowish white. 



A series of over thirty skins now before me, all taken at one locality and 

 on the same day, show a great range of individual variation in color through 

 the varying intensity of ihe fulvous suffusion. In some specimens, it is a very 

 , lie wash of yellowish-brown, while in others u is strongly yellowish, which, 

 iu still others, becomes decidedly rufous, especially on the sides of the neck 

 and shoulders and on the top of the head. In one specimen (No. 2841, M. 

 C. Z. Coll.), the whole upper surface of the head is bright chestnut, and thn 

 usual pale fulvous suffusion on other parts of the body is decidedly rufous, 

 rather than fulvous. No. 2763 (M. C. Z. Coll.) is strongly tinged throughout 

 with yellowish-brown. On the other hand. No. 2682 (M. C. Z. Coll.) has 

 only a faint yellowish-brown tinge, which is scarcely perceptible on the ven- 

 tral surface. These specimens are, however, ali adult males. There is 

 apparently no sexual difference in color ; some of the palest specimens, as well 

 as the brightest, being males. Young specimens differ from the adult in 

 being generally more grayish, with fewer black-tipped hairs in the dorsal 

 surface. The fulvous suffusion is generally paler, but in some specimens is 

 as bright as in average adults 



The texture of the pelage is much as in the Arvicola, especially the 

 large A. xanthognathus, being much firmer than in the Hares, with a much 

 smaller amount of soft under-fur. 



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