Thanks, gentlemen, for your even-handed approach to this problem.
Speaking of Shackelford, it just so happens that that is where I picked up a
live, sinistral Busycon yesterday. I scanned it, just out of my freezer. No,
I'm afraid it's not a living fossil; doesn't have the character of John
Timmerman's Shackelford beasts. This is typical sinistrum.
The thing I noticed was its yellow aperture with contrasting violet stripe,
unlike Phil's description of a generally white aperture.
I'll send a jpeg of the scans to Bill and Phil and to anyone who would like
to see.
(What's B. laeostomum look like? You surprised me once again--with a new
Atlantic whelk species in my old neighborhood, Harry.)
David