hydroid

hy·droid  (hdroid)

n.

1. Any of numerous characteristically colonial hydrozoan coelenterates having a polyp rather than a medusoid form as the dominant stage of the life cycle.

2. The asexual polyp in the life cycle of a hydrozoan.

adj.

Of, relating to, or characteristic of a hydroid.

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[hydr(a) + -oid.]

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hydroid  (hdroid)

Any of numerous, usually colonial marine coelenterates of the order Hydroida, having a polyp rather than a medusoid form as the dominant stage of the life cycle. Hydroids have a simple cylindrical body with a mouthlike opening surrounded by tentacles. Most species form colonies with individual hydroids branching off from a common hollow tube that is probably used to share ingested food. The young develop from eggs or from buds. The most well-known hydroids are the hydras (genus Hydra), which are atypical in being both freshwater and solitary.

Thesaurus

Noun

1.

hydroid - colonial coelenterates having the polyp phase dominant hydrozoan cnidarian, coelenterate - radially symmetrical animals having saclike bodies with only one opening and tentacles with stinging structures; they occur in polyp and medusa forms planula - the flat ciliated free-swimming larva of hydrozoan coelenterates class Hydrozoa, Hydrozoa - coelenterates typically having alternation of generations; hydroid phase is usually colonial giving rise to the medusoid phase by budding: hydras and jellyfishes hydra - small tubular solitary freshwater hydrozoan polyp siphonophore - a floating or swimming oceanic colony of polyps often transparent or showily colored sertularian - feathery colony of long-branched stems bearing stalkless paired polyps