I agree with David, these look like very worn specimens of _Ostrea edulis_.
The ligament area often looks odd as the wear makes several layers visible
at once.

Liz Somerville

--On 14 May 2007 09:36 -0500 David Campbell <[log in to unmask]> wrote:

>> And Marie (UK) needs verification of 2 (Possibly Saddle Oysters) for a
>> project - See:
>>
>> http://www.manandmollusc.net/Mystery_shell_pages/marie-mystery.html
>>
>
> The shells look rather thick for Anomia, and the bottom one definitely
> has an oyster-like ligament area.  Ostrea edulis is the standard
> European oyster, though various oyster species are widely introduced
> and might be present.
>
> --
> Dr. David Campbell
> 425 Scientific Collections
> University of Alabama
> "I think of my happy condition, surrounded by acres of clams"
>
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