Descriptions of East Asiatic Mammals 245 
buffy tips, becoming reddish toward the membranes. The 
undersurface is burly white, also touched with reddish toward 
the membranes. The ears are black, with a chestnut patch at 
the base, and the hands and feet are reddish. The color of the 
tail is mixed bufTy and black, the tip black. The length of head 
and body amounts to 13 inches, tail 15 inches, and foot 2% 
inches. 
The White-cheeked Giant Flying Squirrels, Petaurista 
leucogenys and allies, of Japan and the adjoining mainland, 
form a thoroughly distinct group within the genus Petaurista: 
The Japanese White-cheeked Flying Squirrel, Petaurista 
leucogenys, the first of its group ever described, has the upper 
surface smoky gray, with the hairs white-tipped. A gray-white 
cheek patch on either side of the head passes between the eye 
and the ear and extends onto the side of the neck. The throat 
and underparts are white, becoming russet-tinged on the mem- 
branes and the inner sides of the limbs. The tail is gray. The 
length of the head and body is about 17 inches, the tail ±14 
inches. Several other forms on various of the Japanese islands 
are distinguished by variations in the size and shape of the white 
cheek mark, of the body color, and by differences in the propor- 
tion of the tail length to the length of the head and body. 
The Korean White-cheeked Flying Squirrel, P. I. hintoni, 
is colored a more reddish brown than the Japanese form, and its 
tail is shorter. The color of the tail is paler than the back. The 
underparts are white, becoming reddish toward the edges of the 
membranes. The length of the head and body is 19 inches, of 
the tail only 9% inches, hind foot 2% inches. 
The Manchurian White-cheeked Flying Squirrel, Petau- 
rista watasei of southern Manchuria, has a longer tail than P. I. 
hintoni and is grayish brown. The underparts are grayish white, 
becoming salmon-buff on the membranes. The length of the 
head and body is 17 x /2 inches, tail l^ 1 /^ inches, foot 2% inches. 
