Just as radial symmetry is most noticeable in sea stars, sea stars are also the most well known of all echinoderms. Sea stars live in all oceans and in virtually all zones within the reef. 

Like the brittle stars, sea cucumbers perform a valuable function by constantly removing detritus from the substrate. 

There are over 800 different species of sea urchins varying greatly in appearance, ranging in size from less than an inch to over a foot across in an assortment of shapes and colors. 

While sea urchins may be considered the brutes of the echinoderms, feather stars are the delicate flowers of the group.