224 
THE CABINET OF NATURAL HISTORY, 
ral expansions, supported anteriorly and posteriorly by the 
limbs between which they are extended, and by peculiar 
bony processes arising from the feet. These expansions 
are not naked and membranous like those of the bats, but 
are actual continuations of the skin clothed externally by 
a dense fur similar to that which invests every other part 
of the body. Neither do they serve, like the flying mem- 
branes of many of the bats, the purposes of wings; their 
functions being limited to that of a parachute, giving to 
the animal a considerable degree of buoyancy, and thus 
enabling it to take leaps of almost incredible extent, 
through which it passes with the velocity of an arrow. 
The name of Flying Squirrels is consequently founded on 
an erroneous assumption; but it may nevertheless be admit- 
ted as a metaphorical expression of their most distinguish- 
ing peculiarity. 
The Flying Squirrels were but little known to the earlier 
naturalists. Even down to the time of Linnaeus no clear 
distinction was made between those of America and the 
Polatouche of Siberia and northern Europe. It was Pal- 
las who first pointed out with precision the actual differ- 
ences between the latter and the more common of the Ame- 
rican species, which had been figured by Buffon under 
the Polish name in the erroneous idea that it was really 
the Polatouche. A third species was indicated by Foster 
in a brief notice of a collection made in Hudson’s Bay, 
published in the Philosophical Transactions. This has 
since been more fully characterized by Dr. Richardson, 
who, however, appears to be by no means satisfied of the 
correctness of its separation from the species found in the 
north of the Old Continent. The same distinguished tra- 
veller had himself added a fourth to the list from the val- 
leys of the Rocky Mountains; but he has subsequently re- 
duced it to the rank of a variety only, and offers a guarded 
opinion that both it and the last may, without much vio- 
lence, be united to the Polatouche. In that case the Fly- 
ing Squirrels of the temperate zone would all be still re- 
ferable to the two species originally established by Pallas. 
They closely agree in general form with the true Squirrels; 
but are of a smaller size, have rounder heads, and larger 
and more prominent eyes. 
The lesser Flying Squirrel is little more than half as 
large as the more northern species, from which it also dif- 
fers in many particulars of form, colouring, and habits. 
Its tail is longer in proportion, measuring three-fourths of 
the length of the head and body; and its head is somewhat 
more produced in front. On its upper surface the animal 
is of a bright mouse-colour, with a tinge of fawn, which is 
entirely wanting in the other species; the under surface is 
nearly pure white. The lateral expansions have fawn- 
coloured margins, bordering a black band; and with only 
a slight rounded lobe at their anterior extremity on either 
side. The tail is of the same colour as the body, but more 
dusky beneath; the eyes are surrounded by broad black 
circles; the whiskers are long and black; and the ears rather 
large, somewhat pointed at the tips, and nearly naked on 
the surface. The length of the head and body never ex- 
ceeds five inches. 
Like the other Squirrels these animals feed on nuts, 
acorns, and young shoots. Of the former they store up 
a sufficient quantity for their winter subsistence in their 
nests, which are built on trees in a very artificial manner, 
and are each capable of containing several individuals. 
They seldom stir out during the day, but become lively 
and active during the night, foraging in parties of ten or 
twelve, and bounding from tree to tree with astonishing 
agility. “They will fly,” says Catesby, “fourscore 
yards from one tree to another. They cannot rise in their 
flight, nor keep in a horizontal line, but descend gradual- 
ly, so that in proportion to the distance the tree they de- 
sign to fly to is from them, so much the higher they mount 
on the tree they fly from, that they may reach some part 
of the tree, even the lowest, rather than fall to the ground, 
which exposes them to peril. But having once recover- 
ed the trunk of a tree, no animal seems nimble enough to 
take them.” In captivity they seem to be perfectly happy 
and contented, and though shy at first, soon become fami- 
liar with those who treat them with kindness. 
[ Gardens of Zoological Society. 
EMIGRATION OF BIRDS. 
Amongst the dispensations of an inscrutable Provi- 
dence, the migrations of birds is not the least wonderful, 
and must be interesting to the sportsman, as well as to the 
philosopher. While we are perfectly aware of the facts, 
we are at a loss to account for the manner in which an ani- 
mal apparently incapable of a journey even of an ordinary 
length, continues to make its way over an amazing extent 
of unfathomable ocean. Perhaps the most extraordinary 
part of this mysterious circumstance is, that while those 
birds, whose superior powers of wing seem in some de- 
gree calculated for these extraordinary flights, are not un- 
frequently observed in their passage, there are others, that 
appear altogether incapable of flying five miles, which 
nevertheless make their way over an extent of ocean, per- 
haps of five hundred miles! 
That sea fowl, adapted either for flying or swimming, 
and whose food is always near, should take long journies, 
seems reasonable enough, from their evident powers to 
