What is "didelphis"

Didelphys \Di*del"phys\, n. [NL. See Didelphia.] (Zo["o]l.) Formerly, any marsupial; but the term is now restricted to an American genus which includes the opossums, of which there are many species. See Opossum. [Written also Didelphis.] See Illustration in Appendix.
--Cuvier.

The six species in the genus Didelphis, commonly known as large American opossums, are members of the order Didelphimorphia. The genus is composed of cat-sized omnivorous species, and are recognized on their prehensile tails and the tendency to "play possum" (feign dead) when cornered. The largest species, the Virginia opossum, is the only marsupial to be found in North America north of Mexico.