Strange sea biscuit found on North Carolina Coast… What is it?

[ShellSeeker9]

[attachment=155][attachment=156][attachment=157]Can anyone help me identify this shell?  It looks like a sea biscuit of some sort, but the pattern does not match anything else I've seen on the internet.  I also found a fragment of a similar shell nearby (to the right in the first pic).  Thanks so much for your help!

[paul monfils]

It's a species of Echinocardium, but there are a lot of similar species, and I'm no expert on echinoderms.  It looks a lot like E. fenauxi, but as far as I know that species lives on the other side of the Atlantic.

http://www.echinoids.nl/Echinoids/Echino...enauxi.htm

[ShellSeeker9]

Thank you for your information!  We believe it to be the E.fenauxi.  It being found on the east coast in North Carolina, do you know of anywhere we could report our rare finding?

We are so excited to have found the specimens we have.

Thanks

[paul monfils]

Apparently I was incorrect about Echinocardium fenauxi occurring only in the eastern Atlantic.  Here's a record of a specimen in the Smithsonian that was collected off North Carolina: 
http://collections.si.edu/search/record/...ogy_345296
Not too surprising. There are a number of mollusk species which likewise occur on both sides of the Atlantic.