NATURAL SCIENCES OF PHILADELPHIA. 321 



very light colored a pale yellowish cinnamon ; others approach 

 mouse color, but even in the darkest specimens the decided ful- 

 vous shade appears at least upon the sides. All this colored por- 

 tion is plumbeous beneath, excepting a little space along the 

 middle of the sides, where basally white hairs have the tawny 

 tips. All the under surface of the animal is snow-white to the 

 roots of the hairs. The line of white begins on the side of the 

 muzzle and runs along the side of the head, including the pouch ; 

 the entire fore limb is white ; the stripe rises a little on the side 

 of the belly, and thence runs along the middle of the outside of 

 the hind limb from the knee to the heel, sending a sharp white 

 stripe from the knee across the haunches to the root of the tail. 

 The hind foot is white, with a dusky stripe along the sole. The 

 whiskers are partly black, partly colorless ; their conjoined bases 

 make a conspicuous black spot on each side of the muzzle. There 

 is some whitishness in most cases sometimes altogether wanting 

 about the eye, and a white patch just back of the ear. The front 

 of the ear is sometimes light. The tail is dusky-slaty, or sooty- 

 brown, or even blackish, with a broad, firm white stripe on each 

 side from base to near the tip. At the extreme base, the white 

 usually encircles the tail ; at the other end, the color of the tuft is 

 altogether indeterminate ; sometimes the white lateral stripes give 

 out before reaching the end, leaving the tip entirely dark ; some- 

 times the white extends to the very end of the brush, cutting off 

 the dark altogether; and moreover, the white ma} 7 encroach upon 

 the under side, cutting off the dark from more than half the tail ; 

 oftener, the brush is mixed dusky and white. Thus the tail ma} 7 

 end either white or dark, or a mixture of both. It is as variable 

 in this respect as the tail of a skunk. The eyes are lustrous 

 black ; the nose pad and palms flesh colored ; the claAvs pale. 



In old museum specimens, long exposed to the light, the above 

 description may not be verifiable as regards any of the darker 

 markings and shades mentioned ; for all the colored portions of 

 the fur finally fade to a dull, pale brownish-j-ellow, or even dingy 

 yellowish-white. Under such circumstances, even the rich pur- 

 plish chestnut of a mink, for example, ends in ding} 7 whitish. 



Having thus fully exposed the general characters of the ani- 

 mals of this genus, it remains to consider the mode in wdiich and 

 extent to which the genus has become differentiated into recog- 



