4 
PTEROMYS GENIBABBIS. 
Between the anterior extremities and the head, no vestige of a flying-tnembrane 
appears; in the Sciurus Sagitta, on the contrary, as described by Linnaeus, the 
membrane is extended from the head to the wrists. In its expansion, between the 
extremities, the membrane is bordered by a beautiful fringe, consisting of delicate 
hairs, of a lighter colour than the fur of the animal generally, very closely arranged, 
and diverging in a horizontal or slightly curved direction. This border is more full 
and compact along the posterior extremities. At the termination of the cartilaginous 
support near the wrist, it constitutes a delicate broad brush or penicillus. The feet, 
as in other species of Pteromys, project beyond the membrane ; the fore-feet consist 
of four toes, and a very obscure rudiment of a thumb. The toes are slender, com- 
pressed, and armed with broad, strongly curved, and very sharp claws. The two 
middle toes are somewhat longer than the exterior, which are nearly of equal length. 
An elevated, circular, warty protuberance exists on the extremity of the first 
phalanx, above the articulation. On the posterior extremities, the feet are divided 
into five toes, which are somewhat lengthened, but in other respects agree in cha- 
racter with those on the anterior extremities. They admit of free motion ; the small 
toe is nearly as long as the intermediate toes ; the thumb is smaller, and somewhat 
removed from the other toes. The warty protuberance on the extremity of the first 
phalanx, is most conspicuous on the small toe. 
The tail equals in length nearly t wo-thirds of the body of our animal. It is 
compressed, oblong, somewhat broader in the middle, and truncated at the extremity . 
The separate hairs which cover it, are arranged loosely, in a distichous manner, or 
spreading from the middle to the sides ; they are long, delicate, silky, slightly 
undulated, and numerous, affording to this organ a degree of fulness, which is 
highly ornamental. 
The general covering of our animal is very beautiful. The fin* consists of long 
hairs, downy at the base, closely arranged on the neck and back, more distant on 
the flying-membrane. For an animal inhabiting a hot climate, this fur is uncommonly 
thick ; it possesses indeed the delicacy and fulness of the fur of an animal from the 
northern regions. Solitary bristly hairs project in many parts from the downy 
covering. On the under parts the texture of the hair generally is more lax and 
delicate ; it is woolly on the throat, breast, and abdomen ; on the hypochondria, 
and on the flying-membrane, it is loose and straggling. 
The general colour of the fur of our animal is gray on the upper parts, and 
white underneath ; the head, above, is purely gray ; on the neck, the back, and the 
tail this colour has a brownish tint, inclining to tawny ; the anterior and middle 
