HYDRACTINIAN


Meaning of HYDRACTINIAN in English

noun any species or marine hydroids, of the genus hydractinia and allied genera. these hydroids form, by their rootstalks, a firm, chitinous coating on shells and stones, and ·esp. on spiral shells occupied by hermit crabs. ·see ·illust. of athecata.

Webster English vocab.      Английский словарь Webster.