whose waving rays resemble little feathers. And there are the ordinary sea stars which usually measure about13 centimeters.
The tough, leathery skin of a starfish is covered with very short spines. In the center of their bodies are disk-like buttons. Through these disks they draw in or push out sea water. The disks on the underside act as mouths. The eyes are at the tips of their arms and are protected by a circle of spines.