__ FLYING SQUIRRELS. 79 



cover their depot when under the snow, which they remove with 

 their paws, and their instinct teaches them not to put all they 

 gather into the same place : ordinarily they make several store- 

 houses, and when one is discovered and robbed, or exhausted, 

 they recur to the others. By their address and agility alone, they 

 succeed in eluding their enemies. The moment they are apprised 

 of their approach by any extraordinary noise, they leave their 

 nest, and through the assistance of their nails, which enables 

 them to adhere to the bark of trees, we see them, in order to 

 escape from the object of their dread, place the thickness of a 

 branch between it and themselves, which makes it difficult to see 

 them, if one is perceived by them ; when we go around the tree 

 to get to the same side upon which they are, they at once pass to 

 the opposite, and if their fear becomes still greater, they cover 

 themselves betwixt two branches and lie motionless. These 

 animals are extremely clean in their habits ; they never soil their 

 nests, and they are continually polishing their hairs with their 

 fore paws, which they employ for many other purposes : it is 

 with these, they convey food to the mouth, and pluck the moss 

 with which they build their nests : in some instances they can 

 oppose their rudimentary thumb with which they are provided 

 to their fingers, so that their paws perform the offices of hands. 

 The great length of their hind legs makes them excellent leapers ; 

 on the ground their progression is effected altogether by leaping ; 

 and to rest, they sit upon their hind legs, elevating the tail and 

 spreading it over their head as a kind of canopy. It is said that 

 they avail themselves of a piece of bark for a boat, and use the 

 tail as a sail when they wish to cross a stream ; but we may be 

 permitted to believe that a stream, even for a free squirrel, when 

 uninfluenced by the fear of danger, will always be a barrier that 

 he will never attempt to pass ; and if he were forced through 

 fear to plunge into the water, swimming would be his only re- 

 source. The voice of the squirrel is a sharp cry, and sometimes 

 he utters a feeble sound, although his mouth be shut, which is 

 said to be a sign of impatience or anger. 



24. The FLYING SGIUIRRELS, Pteromyft, (winged rat) (Plate 

 4, Jig. 8.) have on each side of the body a prolongation of the 

 skin, which extends between the fore and hind legs, and forms a 

 sort of parachute, by the aid of which, these animals can sustain 

 themselves in the air for a few seconds and make extended leaps. 

 One species is found in the forests of Poland and Russia, and one 

 in North America. 



24. What peculiarity characterises Flying Squirrels ? , Where are they 

 found ? 



