WALKER'S MARSUPIALS OF THE WORLD

An expert on these pouched animals introduces the unique niche they occupy in evolution. The author of Walker's Mammals of the World, 5th and 6th editions, from which some of this material has been adapted, describes marsupial orders and distribution from American opossums to Australian wallabies (pictured in b&w photos). Nowak was formerly with the Office of Endangered Species, US Fish and Wildlife Service.