Hydrozoa

Taxonomic class of animals

Hydrozoa (hydrozoans; from Ancient Greek ὕδωρ (húdōr) 'water' and ζώα (zóa) 'animals'), also called hydroids, are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specialized individual animals cannot survive outside the colony. A few genera within this class live in freshwater habitats.

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