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Attached Hydroids (Biotic Group)

Component: Biotic

Unique Identifier: 513

Biotic Setting Benthic/Attached Biota
Biotic Class Faunal Bed
Biotic Subclass Attached Fauna
Biotic Group Attached Hydroids
Biotic Community Attached Sertularia
Attached Tubularia

Definition Areas dominated by mounds or mats of hydroids that are attached to a hard substrate. Hydroids are colonies of individual cylindrical polyps arranged in a branching structure, as a furry or brushy covering, or in other forms. Polyps are specialized for support, reproduction, and defense, and are armed with nematocysts (stinging capsules in specialized cells). Hydroids are the benthic life stage of planktonic jellyfish medusae, and most are predators on small life forms. Hydroid mounds or mats may form very dense assemblages.