Blue Bivalve shell with long worm thing!

[sally]

A log on the shore line in Wales, UK was covered in pale blue bivalve shells, with a dark blue line around, and a worm type thing attached. The "worm" was about 6-8" and about 1/2" thick, and the shell was attached near one end, with a sort of "tail" inside, that sometimes unfurled to reveal a fin shape end. The whole log was covered completely. Anybody know what they might have been, as I cannot find any reference to them anywhere? Unfortunately I have not got a picture.

[paul monfils]

Hi Sally,

Your descrïption sounds like brachiopods, a strange group of animals sometimes commonly referred to as "lamp shells".  They do have a bivalved shell, as you said, but they have no relationship to most of the bivalves we are familiar with, like clams, cockles, mussels and scallops, all of which are molluscs.  Brachiopods are not molluscs, but members of an entirely different phylum.  Their internal anatomy is completely different from that of a bivalve mollusc. They attach to the substrate by a long stalk - the worm type thing.  Here are a couple of pictures.  See if your critters are similar to these ...

<a href="http://members.cox.net/natura/Lingula1.jpg" target="_blank"><!-- m --><a class="postlink" href="http://members.cox.net/natura/Lingula1.jpg">http://members.cox.net/natura/Lingula1.jpg</a><!-- m --></a>

<a href="http://members.cox.net/natura/Lingula2.jpg" target="_blank"><!-- m --><a class="postlink" href="http://members.cox.net/natura/Lingula2.jpg">http://members.cox.net/natura/Lingula2.jpg</a><!-- m --></a>

Chances are the log you found on the beach came from the Caribbean and was carried up the eastern coast of the United States in the Gulf Stream, turning eastward at Cape Cod, and continuing across the North Atlantic until reaching the UK.  <span class="petit">--Last edited by Paul Monfils on 2007-08-27 19:06:37 --</span>