zoanthidhttp://www.oed.com/dictionary/zoanthid_n%3Ftab%3Dmeaning_and_usezoanthid, n.
First published 1921; not fully revised

zoanthidnoun

Zoology.
  1. 1870–
    A member of the family Zoanthidæ of zoantharians, typified by the genus Zoanthus.
    Stressed as zoˈanthid.
    1. 1870
      Structures supposed to be gills are developed in some Zoanthids on either side of the primary mesenteries.
      H. A. Nicholson, Manual of Zoology (1875) xiii. 132

Originally published as part of the entry for zoantharian, adj. & n.

zoantharian, adj. & n. was first published in 1921; not fully revised.