echinoderm

e·chi·no·derm  (-kn-dûrm)

n.

Any of numerous radially symmetrical marine invertebrates of the phylum Echinodermata, which includes the starfishes, sea urchins, and sea cucumbers, having an internal calcareous skeleton and often covered with spines.

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e·chino·dermal, e·chino·derma·tous (-dûrm-ts) adj.

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echinoderm [ik-kine-oh-durm]

Noun

a sea creature with a five-part symmetrical body, such as a starfish or sea urchin [Greek ekhinos sea urchin + derma skin]

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echinoderm  (-kn-dûrm)

Any of various marine invertebrates of the phylum Echinodermata, having a latticelike internal skeleton composed of calcite and usually a hard, spiny outer covering. The body plans of adult echinoderms show radial symmetry, typically in the pattern of a five-pointed star, while the larvae show bilateral symmetry. Echinoderms probably share a common ancestor with the hemichordates and chordates, and were already quite diversified by the Cambrian Era. They include the starfish, sea urchins, sand dollars, holothurians (sea cucumbers), and crinoids, as well as thousands of extinct forms.

Thesaurus

Noun

1.

echinoderm - marine invertebrates with tube feet and five-part radially symmetrical bodies invertebrate - any animal lacking a backbone or notochord; the term is not used as a scientific classification water vascular system - system of fluid-filled tubes used by echinoderms in locomotion and feeding and respiration Echinodermata, phylum Echinodermata - radially symmetrical marine invertebrates including e.g. starfish and sea urchins and sea cucumbers ambulacrum - one of the five areas on the undersurface of an echinoderm on which the tube feet are located sea star, starfish - echinoderms characterized by five arms extending from a central disk brittle star, brittle-star, serpent star - an animal resembling a starfish with fragile whiplike arms radiating from a small central disc basket fish, basket star - any starfish-like animal of the genera Euryale or Astrophyton or Gorgonocephalus having slender complexly branched interlacing arms radiating from a central disc sea urchin - shallow-water echinoderms having soft bodies enclosed in thin spiny globular shells crinoid - primitive echinoderms having five or more feathery arms radiating from a central disk holothurian, sea cucumber - echinoderm having a flexible sausage-shaped body, tentacles surrounding the mouth and tube feet; free-living mud feeders tube foot - tentacular tubular process of most echinoderms (starfish and sea urchins and holothurians) having a sucker at the end and used for e.g. locomotion and respiration