One member of this phylum, Strongylocentrotus purpuratus, is often used to study developmental processes, and another, Pisaster ochraceus, is an example of a keystone species. Most members of this phylum have pedicellariae that possess three jaws, and some have a chewing apparatus known as Aristotle's lantern. Members of class Asteroidea of this phylum have an ambulacral groove, and the madreporite is the entrance to their water vascular system that includes tube feet. FTP name this phylum whose "spiny skinned" members 
One member of this phylum, Strongylocentrotus purpuratus, is often used to study developmental processes, and another, Pisaster ochraceus, is an example of a keystone species. Most members of this phylum have pedicellariae that possess three jaws, and some have a chewing apparatus known as Aristotle's lantern. Members of class Asteroidea of this phylum have an ambulacral groove, and the madreporite is the entrance to their water vascular system that includes tube feet. FTP name this phylum whose "spiny skinned" members have radial symmetry and include sand dollars, sea urchins, and sea stars.
One member of this phylum, Strongylocentrotus purpuratus, is often used to study developmental processes, and another, Pisaster ochraceus, is an example of a keystone species.
{Echinodermata} [accept {echinoderm}s]