Is this a shell?

[Carbon]

Hi, I was walking on the beach in the north coast of Scotland and came across this delicate looking item, I'm not sure if it is a shell or some kind of egg.
I have never seen one before.
Anyone know what it is? Thanks.

[img width=209 height=480]http://i51.tinypic.com/fx5o5w.jpg[/img]

[paul monfils]

It's a "shell" in the broad sense, but not a mollusk shell.  This is a "test" ("shell") of a heart urchin, an echinoderm, a phylum of animals that also includes sea urchins and sea stars.  In life it was covered with small slender spines which made it look "fuzzy" or "velvety".  I don't have much expertise regarding species of this group, but I think it may be this one:

<!-- m --><a class="postlink" href="http://www.seawater.no/fauna/echinodermata/cordatum.html">http://www.seawater.no/fauna/echinoderm ... datum.html</a><!-- m -->