hydractinian

hydractinian is defined in Webster's Unabridged Dictionary (1913) with 1 sense. The full text of each entry is reproduced verbatim below.

Definitions

  1. 1.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.

Source: Webster's Unabridged Dictionary, 1913 edition (public domain, via GCIDE / Project Gutenberg).

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