zonoplacentalhttp://www.oed.com/dictionary/zonoplacental_adj%3Ftab%3Dmeaning_and_usezonoplacental, adj.
First published 1921; not fully revised

zonoplacentaladjective

Zoology.
  1. 1879–
    Having a zonary placenta, as the Carnivora and other mammals: opposed to discoplacental.
    Stressed as zonoplaˈcental.
    1. 1879
      Man, apes, bats, insectivora, and rodents..form a natural group to which no zonoplacental, and, of course, no indeciduate mammals can be admitted.
      translation of A. de Quatrefages de Bréau, Human Species xi. 109

Originally published as part of the entry for zono-, comb. form

zono-, comb. form was first published in 1921; not fully revised.