> First, it would be nice to know where you collected them.  However, if all
> were found in the same locale and the adult has ridges over the entire
> shell, you probably are collecting M. campechiensis (Gmelin, 1791).  M.
> mercenaria has a smooth center in the large shells.  M. m also frequently
> has purple on the interior, but very rarely so for M. c.  There was a named
> form (notata Say) that has a brown zigzag pattern on the exterior, which can
> be sparse or cover almost all the shell.  In my experience the pattern
> persists in the adult shell.  I've found that for both the ridges are more
> pronounced in the juveniles.

I used to think I had the notata form until I saw the real thing, now being
cultivated for farming at Harbor Branch. The notata look more like M
mercenaria - smoothish on the middle of the valve, and the brown zigzags are
very definite.

I'm pretty sure Linda has juveniles of M mercenaria or campechiensis

Peggy
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                                  Peggy Williams
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