squirrels.

The _Ground Squirrels_ differ from the true squirrels in several
respects, though the chief difference lies in the fact that the former
make their nest or lair upon the ground, while the latter universally
lodge themselves aloft among the branches. The Ground Squirrels can
climb, and appear to ascend trees almost as nimbly as their congeners;
but they rarely do so unless when pursued, and then but seldom go beyond
the lower forks or branches. Their nest is usually in some hole or
cavity among the roots, though several species have been lately
discovered in rocky regions, dwelling in the crevices of rocks. They
approach in habits to the marmot tribe, and seem to link the tree
squirrels with these last. Usually, these ground squirrels are striped
longitudinally with black, red, and white stripes, giving them a fine
appearance; and the species are of different dimensions, from that of
the ordinary squirrel to the size of a mouse. In America, for a long
time, but one kind was supposed to exist; but latterly a great number of
species have been observed and described: denizens of the far West--of
the prairies, and remote valleys of the Rocky Mountains.

The African species of ground squirrel, already mentioned as the Palm
Squirrel, has its dwelling among the palm trees, on the fruit and roots
of which--especially that of the date-palm--it subsists. It is also an
inhabitant of India, where there is at least one other species of palm
ground squirrel.

In Europe, and throughout the whole of Northern Asia, the ground
squirrels are represented by the _burunduk_--a very interesting little
species, quite similar in habits to those of North America.

The _Flying Squirrels_ are the last of the group. These are the most
singular of all, and resemble great bats more than squirrels. They
possess the power, not exactly of flight, but of making very long leaps
from a higher to a lower level, so long that they might almost be
regarded as flights. They can pass from one tree to another standing
more than a hundred yards apart, and this without descending more than a
few feet below the level from which they started. This feat they are
enabled to perform by means of a broad membrane that extends from the
skin of their fore-legs to that of their thighs, and which, when
stretched out, endows them with the properties of a parachute. Their
bodies, too, have a flattened shape like the bats; and this also helps
to sustain