I have a large one (1.8cm) I found growing inside a glass jar in a bay
in the Florida Panhandle.  It was alive and intact, so I have both
halves.  I was able to remove it from the jar, and it is smoothly
rounded, just like the inside of the jar.  One of those curious finds
you get about every 10 years or so of looking.
 
Sylvia Edwards
 
PaulCyp wrote:
>
> P.S.  In Anomia, usually only the upper single valves wash ashore.  The lower
> valves are firmly attached to the rocks on which they live, and seldom wash
> ashore.  But occasionally they do.  The lower valve would have a large hole in
> it, right near the hinge, where the byssus that attached it to the rocks
> passed through the shell.
>
> Paul M.