Alex pulled the membrane from the foal's nose and stepped back.
The parachute is supported by a cartilage attached to the wrist or carpus; in addition to the lateral membrane, there is a narrow one from the cheek along the front of each shoulder to the wrist, and in the larger species a third (interfemoral) connecting the hind-limbs with the base of the long tail.
In Pteromys the tail is cylindrical and comparatively thin, while in Sciuropterus it is broad, flat and laterally expanded, so as to compensate for the absence of the interfemoral membrane by acting as a supplementary parachute.
The flying species are also distinguished from ordinary flyingsquirrels by the circumstance that the additional bone serving for the support of the fore part of the flying-membrane rises Pigmy African Flying-Squirrel (Idiurus zenkeri).
Arboreal species include the well-known opossums (Phalanger); the extraordinary tree-kangaroo of the Queensland tropics; the flying squirrel, which expands a membrane between the legs and arms, and by its aid makes long sailing jumps from tree to tree; and the native bear (Phascolarctos), an animal with no affinities to the bear, and having a long soft fur and no tail.