Topic summary
Patagia

Extracted from the Wikipedia article Patagium.
Gliding mammals
Flying squirrels, sugar gliders, colugos, anomalures and other mammals also have patagia that extend between the limbs; as in bats and pterosaurs, they also possess propatagia and uropatagia. Though the forelimb is not as specialised as in true flyers, the membrane tends to be an equally complex organ, composed of various muscle groups and fibers. Various species have styliform bones to support the membranes, either on the elbow (colugos, anomalures, greater glider, Eomys) or on the wrist (flying squirrels).