I started this thing---so I get to comment from time to time.
What I am thinking about is being able to distinguish shells down to
the Sub-generic level. (How to tell a Plotzconus from an Umlautconus)
NOT how to distinguish at the species level. You individual experts can
do that. I'm thinking about a book that shows the distinguisments AND
illustrates them---where to look on the shell. What numbers are we
talking about? What numbers are we talking about if we limit it to
univalves?
Q-Man