semioviparous

from The American Heritage® Dictionary of the English Language, 4th Edition

• adj. Bearing living young that are incompletely developed, as a kangaroo or other marsupial.

from The Century Dictionary and Cyclopedia

• Imperfectly viviparous, as an implacental mammal: noting the marsupials and monotremes (the latter, however, have been ascertained to be oviparous).