Any of many radially symmetrical marine invertebrates associated with phylum Echinodermata, including the starfishes, sea urchins, and sea cucumbers, having an interior calcareous skeleton and frequently covered with spines.
Any member of the Echinodermata, a small grouping of radially symmetric, spiny-skinned marine pets. Types of echinoderms feature seastars, sea urchins, water cucumbers, crinoids, and sand bucks.
Any one for the Echinodermata.
marine invertebrates with tube foot and five-part radially shaped systems