That is not quite right look here http://naturalhistory.museumwales.ac.uk/britishbivalves/browserecord.php?-recid=107 . I work in M. edulis culture, and what you showed us is the typical juvenile.
Cheers
Antonio

Sent from my iPad

On Apr 25, 2012, at 23:20, David Campbell <[log in to unmask]> wrote:

> Try Perna perna, already invasive in various regions.  The not quite
> terminal beak also doesn't match M. edulis very well.
>
> On Tue, Apr 24, 2012 at 10:59 PM, Paul Mikkelsen
> <[log in to unmask]> wrote:
>> I've been asked for help with an ID on a mytilid bivalve, and need input
>> from others.
>> Here's what I know about the clams:
>>
>> They came from a water intake on a large vessel docked in Fort Lauderdale,
>> Florida, USA.  They were in such numbers, they were described as an
>> "infestation".  We know that the vessel visited the following ports: Nassau,
>> Charleston, New Port, Cape Cod, Portland (Maine), Bar Harbor (Maine),
>> Halifax, Prince Edward Island, and Boston.   Cruising dates included 11 June
>> to August 12, but it's unknown where the vessel was at what time, or if the
>> vessel made it to all the above ports in that amount of time.
>>
>> Additionally, it may have also traveled into other areas of the Caribbean or
>> even the other side of the pond (so we can't rule out the Mediterranean).
>>
>> The photographed specimen's longest dimension is 9.6 mm;  I have a few
>> others that size and smaller.  I don't know if/when the vessel's intake had
>> been cleaned prior to the mussel "infestation" and thus can't speculate on
>> their age.
>>
>> The following links (hoping one works!) should take you to the same photos.
>> View Album
>>
>> Play slideshow
>>
>> https://picasaweb.google.com/lh/sredir?uname=108580848782880140183&target=ALBUM&id=5735160855975191697&authkey=Gv1sRgCLHN3qmnr-iq0gE&feat=email
>>
>> Any help/guidance/guess is appreciated!
>> Thanks!
>> Paul Mikkelsen
>
>
>
> --
> Dr. David Campbell
> Collections Assistant
> The Paleontological Research Institution
> 1259 Trumansburg Road
> Ithaca NY 14850
>
> ----------------------------------------------------------------------
> [log in to unmask] - a forum for informal discussions on molluscs
> To leave this list, click on the following web link:
> http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
> Type your email address and name in the appropriate box and
> click leave the list.
> ----------------------------------------------------------------------

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------