Also found in: Wikipedia.
|n. pl.||1.||(Zool.) A division of hydroids comprising those which have the hydranths in thecæ and the gonophores in capsules. The campanularians and sertularians are examples. Called also Thecata. See Illust. under Hydroidea.|
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.