Meaning of implacental

im•pla•cen•tal

Pronunciation: (im"plu-sen'tl), [key]
— adj.
  1. having no placenta, as a monotreme or marsupial.
—n.
  1. an implacental mammal.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.