What are the characteristics of echinoidea?
What are the characteristics of echinoidea? Echinoidea is a class that belongs to the phylum Echinodermata. Species that belong to this class are the sand dollars, cake urchins, sea urchins, and heart urchins. Echinoids have an egg shaped, circular body which is hemispherical. They have skeletal plates that bear many movable spines and three jawed pedicellariae. What is unique about echinoidea? A distinguishing feature of the echinoids is that the ossicles imbricate (overlap) and are fused into a globular or discoidal test; its flattened or concave oral side faces the substratum and the aboral side is arched in most species....