arcity of such accommodation; and the Horseshoe Bats show
a decided preference for caverns and deserted quarries; but the great
majority appear to be indifferent in the matter, and to resort to any
shelter that seems convenient to them. Some, such as the Barbastelle
of the southern parts of England, are solitary in their habits,
generally retiring alone for their day's rest; others are more
sociable, reposing in larger or smaller parties in their dormitories,
whether natural or artificial, and sometimes, like the Fruit Bats,
collecting in immense numbers.

The common Bats, like the Fruit Bats, sleep in what we should consider
an exceedingly uncomfortable position, namely, with their heads
downwards, but they cling by the claws of _both_ hind feet to the
small irregularities of the stone or wood forming the walls and other
parts of the structure of their retreat. They frequent the same places
year after year, so that, where they are numerous, the ground is often
completely covered and discolored with their excrements, which in some
cases accumulate in course of time to such an amount as to have given
rise to the notion of carrying it away to be used as guano. The little
blood-sucking Vampire Bats already mentioned take up their abode in
caverns, and, according to Dr. Hensel, who observed their habits, they
discharge their excrements, which are black and pasty, near the
entrance of the cave just before starting on their evening flight, and
this substance by degrees forms quite a thick layer (one foot or more)
on the floor of the cavern. The Doctor says that a large dog which had
paid a visit of curiosity to one of these caves came out again looking
as if he had got long black boots on.

In the warmer regions of the earth's surface, where their supply of
food is constant, the activity of the Bats is not known to have any
intermission, but in cold and temperate countries they pass the winter
season in a state of torpidity. The period of this hibernation, as it
is called, varies somewhat in the different species, but few of them
are to be seen flying about, except when the weather is decidedly
mild. The commonest of all our British species, the Pipistrelle, has a
shorter winter sleep than any of its companions, it usually makes its
appearance on the wing by the middle of March, and continues active
until quite late in the year; in fact Mr. Gould has recorded the fact
of his having shot a specimen of it on a warm sunny day j