Some members of this phylum keep their bodies clean through the use of pedicellaria
(pe-deh-sell-AIR-ee-uh). Its species have a system of interlocking calcium carbonate plates calledstereom. Many members of this phylum exhibit (*) pentaradial symmetry, and have tube feet calledpodia. Podia are found at the end of this phylum's main method of movement and respiration, the water-vascular system. Name this phylum of sea cucumbers and starfish, which has a Greek name that describe its members' spiny skin.