nZoanthariaA division (order or subclass) of Actinozoa, containing the hexamerous or hexacoralline forms; the helianthoid polyps, or animal-flowers, contrasted with the Alcyonaria, and characterized by the normal disposition of their soft parts in sixes, or multiples of six (not in eights, as in the Alcyonaria or Octocoralla), and by the possession of simple (not fringed) and usually numerous tentacles: so called from the resemblance of some of them, as the sea-anemones, to flowers. The Zoantharia correspond to the Hexacoralla or Coralligena, and were divided by Milne-Edwards into three suborders (or orders): Malacodermata, with the corallum absent or rudimentary, as in sea-anemones; Sclerobasica, with external non-calcareous corallum, as the black corals of the family Antipathidæ; and Sclerodermata, with internal calcareous corallum, as the ordinary hard corals, or stone-corals. See the technical names.
Chambers's Twentieth Century Dictionary
n.plZoanthariazō-an-thā′ri-a a division of Actinozoa, including the sea-anemones, &c
Webster's Revised Unabridged Dictionary
These are the ALCYONARIA and the ZOANTHARIA.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2" by Various