>         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?
Hundreds of thousands.

What numbers are we talking about if we limit it to
> univalves?
Hundreds of thousands. The ratio of gastropods to bivalves overall is about
4:1.

Dear Santa
What I'd like is a book which explains everything (and everything else too)
in such detail and with such clarity that I never need learn anything else
ever again.
Dear Paul
There are one or two books which actually claim to do this.....