Hi, Bivalve Collectors!

Can anyone give me a description of this shell, or possible scan one and send it to me in jpg?    I think I have several examples of this shell, but they don't  match Abbott's` description in "AmerIcan Seashells," (yes, I know the book has a lot of flaws).   I do have a scanner now but do not have it set up yet.   What I am looking at has some outer markings of
fine brown lines, and sometimes a bluish-purple tinge.   They remind me of a Mercenaria mercenaria with more prominent ridges (that's what I thought I might be dealing with at first; but I have some that are too big to any longer be called "young."
There are NO RADIAL MARKINKS, unlike Chione cancellata.Some of them have some purple inside.   I have similar shells from the Gulf coast of Florida and the Gulf coast of Texas.

Does anyone else feel as if the Venerid clams will  "drive them round the bend?"

Thanks,
Linda - still cataloguing.

I may have even another species mixed in with these, almost the same, but the ridges are much farther apart.   These tend to
run smaller than the ones I described above - or else, I have just not found any bigger ones yet.