any of several phalangers (family Petauridae) with a thin membrane along the sides of the body that enables them to make long, gliding leaps
See flying phalanger in American Heritage Dictionary 4
noun
Any of several small marsupials of the family Petauridae, especially one of the genus Petaurus, native to Australia, New Guinea, and Tasmania and having large folds of skin between the forelegs and hind legs that enable it to glide through the air.