Mon`o*trem"a*ta (?), n. pl. [NL., fr. Gr. single + hole.] Zool.
A subclass of Mammalia, having a cloaca in which the ducts of the urinary, genital, and alimentary systems terminate, as in birds. The female lays eggs like a bird. See Duck mole, under Duck, and Echidna.
© Webster 1913.