Another member of this group, the flying-squirrel, has developed an
extension of the skin uniting the front and hind legs, so it may glide
freely from tree to tree. The bats have gone still further, and the
skin uniting their lengthened front and hind limbs and long finger
bones forms broad wings which lend them powers of flight scarcely
equaled by those of birds.
The gophers, pocket-mice, chipmunks, and others are provided with
little cheek pouches in the skin on each side of the mouth, in which
they may carry food home to their store-rooms and other hiding places.
[Illustration: