I 56 Bulletin American Museum of Natural History. [Vol. XIX, 



toothrow (on alveolar line), 17; length of lower jaw, 67; height of 

 lower jaw, 46. 



Young female, about one third grown. General color above grayish 

 brown with a faint fulvous tinge; the abundant woolly underfur is 

 pale plumbeous at base, with the apical third pale rusty fulvous; the 

 longer overhair is dusky, broadly ringed subapically with white, and 

 ending in a fine blackish tip; ventral surface clothed, from the upper 

 breast posteriorly, with very soft, thick, fine woolly fur, which over the 

 whole pectoral region is pure white to the base, but along the sides and 

 posteriorly is at the base pale plumbeous; a broad prepectoral band 

 dusky grayish brown; chin and throat plumbeous with the fur broadly 

 tipped with white, giving a grayish white superficial tint; sides of the 

 nose and edge of upper lip pale rusty buff; tip of nose dusky, followed 

 as far back as the eyes by a broad facial band of gray; top of head like 

 the back but rather darker; sides of head from nose to base of ears 

 pale grayish rusty buff; ears internally blackish brown washed with 

 pale rust, becoming more fulvous at the tips, which are edged with 

 black; outer border of ears edged with white for the basal three 

 fourths, the white diminishing in amount from the base apically; 

 posterior surface of ears broadly whitish on the outer half, passing into 

 buffy gray on the inner half with the dusky base of the hairs showing 

 more or less at the surface; tail above gray mixed with blackish, under 

 surface of tail light gray; upper surface of fore feet pale yellowish 

 brown, the under surface whitish, adventitiously stained yellowish; 

 hind feet white externally, yellowish brown on the inner edge and on 

 the toes; soles clothed with dusky hairs, the toes yellowish. 



An adult female, taken May 28, is still partly in winter dress, but on 

 the head and back the summer pelage is well developed, though thinly 

 veiled in places by the left-over white hairs of the winter coat, while 

 the nape, shoulders, sides, and whole ventral surface are still heavily 

 covered with the winter coat. The general color of the new, short, 

 summer coat is dark grayish brown suffused rather strongly with 

 buffy yellow. The sparse underfur is pale buffy gray; the longer 

 hairs are broadly banded near the tip with dark brown and tipped with 

 yellowish. The upper surface of the head is rather more yellowish 

 than the back, and the sides are darker, more grayish brown and less 

 yellowish than the back, while the lower back and rump are dark 

 gray. The ears are still mostly white, but the tips have changed 

 from black to dull yellowish brown. The tail is still wholly white, and 

 the feet have undergone little change from the winter dress. 



A male taken October i has nearly completed the change to winter 

 dress. The top of the head and the back show traces of the summer 

 coat, there being a strong mixture of yellowish brown and black- 

 tipped hairs on the crown, and a slight sprinkling of similar hairs over 

 the middle region of the back. 



