echinoderm (redirected from phylum Echinodermata)
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A member of the phylum Echinodermata.
echinoderm any member of the phylum Echinodermata, including the sea urchins, starfish, brittle-stars, sea cucumbers, feather stars and sea lillies. The phylum is characterized by a pentaradiate structure (a five-sided RADIAL SYMMETRY) and the presence of tube feet in most forms.