A sea urchin is covered by long, movable spines. The spines grow from a shell called a <I>test,</I> which lies just under the skin. The test protects the animal's soft body.
<BR><P>
World Book illustration by Patricia J. Wynne</P>
</BODY></P>
<!-- <PT>YES -->
<!-- <AR>From The World Book Multimedia Encyclopedia (TM) (c) «date» World Book, Inc., 525 W. Monroe, Chicago, IL 60661. All rights reserved. -->