246 Mammals of Eastern Asia 
The Orange-footed Flying Squirrels, Trogopterus, with 
typical species T. xanthipes, are medium-sized Flying Squirrels 
found only in China. They have a black tuft of hairs at the base 
of each ear. The body color is chestnut, with the bases of the 
hairs slate, and there is an admixture of some all-black hairs. 
The muzzle and the eye rings are red, the underparts of the 
body whitish. The membranes and the front and hind feet are 
orange-red, whence perhaps the specific name. The length of the 
head and body is 10% inches, of the tail 10% inches, hind foot 
2% inches. The type species is from Hopei. Two other forms 
known in eastern Asia are T. x. edithae from Yunnan and T. x. 
mordax from Szechwan and Hupeh. The former is a grayish 
race from the Likiang Range, the latter a brighter-colored race 
with reddish feet, from the upper Yangtse Valley. There is yet 
another race, T. x. himalaicus, in Tibet. 
The Black Giant Flying Squirrel, Aeromys, like Petaurista, 
has the membrane continued between the forearms and neck, 
and the hind legs and the tail. Robinson and Kloss distinguished 
it from Petaurista mainly by characters of the teeth and skull. 
The digits are hairy beneath. The type species of Aeromys is 
A. tephromelas, with the body and tail black and the bases of 
the body hairs gray. The underparts of the body and the flying 
membranes are gray-brown. The length from the nose to the 
base of the tail is 10 inches, of the tail 11 inches. This animal, 
first described from Penang Island, is also recorded from 
Malacca (Gray). Two other species are known, A. phceomelas 
from Borneo and A. bartelsi from northern Sumatra. 
The Grooved-toothed Giant Flying Squirrel, Aeretes 
melanoptenis (= sidcatus) has the hairs of the back dull brown 
with lead-colored bases, those of the membranes blackish brown. 
The head is lighter and grayer than the back. The hands and 
feet are blackish. The undersurface is gray, tipped with buffy 
except the throat and hind belly, where the hairs have white 
tips. The length of the head and body is 12% inches, tail 13 to 
