Known from the Upper Cretaceous of N. America, Eodelphis is a genus of early opossums, marsupials with long prehensile tails. Opossums are arboreal in habit and are thought to represent the ideal stem stock from which evolved the whole marsupial group. Several species of Eodelphis are known from the Milk River Formation (Upper Cretaceous) of Alberta. The teeth of Eodelphis are sharply cusped and somewhat primitive in form.