Start studying Five Classes of Echinoderms. Learn vocabulary, terms, and more with flashcards, games, and other study tools. read more
Echinoderms are characterized by radial symmetry, several arms (5 or more, mostly grouped 2 left - 1 middle - 2 right) radiating from a central body (= pentamerous). The body actually consists of five equal segments, each containing a duplicate set of various internal organs. read more