MARSUPIALIA
Marsupialia, order Marsupialia
(noun) coextensive with the subclass Metatheria
Source: WordNet® 3.1
Mar*su`pi*a"li*a, n. pl. Etym: [NL., fr. L. marsupium a pouch, bag,
purse, Gr. (Zoรถl.)
Definition: A subclass of Mammalia, including nearly all the mammals of
Australia and the adjacent islands, together with the opossums of
America. They differ from ordinary mammals in having the corpus
callosum very small, in being implacental, and in having their young
born while very immature. The female generally carries the young for
some time after birth in an external pouch, or marsupium. Called also
Marsupiata.
Source: Webster’s Unabridged Dictionary 1913 Edition