implacentalia

1 definition found

implacentalia - Collaborative International Dictionary of English v.0.48 :

  Implacentalia \Im`pla*cen*ta"li*a\, n. pl. [NL. See In- not,
     and Placental.] (Zool.)
     A primary division of the Mammalia, including the monotremes
     and marsupials, in which no placenta is formed.
     [1913 Webster]