As a landlocked shell collector I've rarely seen living shells and so, I
have a few questions that maybe some of you experienced shell collectors
and malacologists can answer:
About Periostraca - what function does the periostracum have, and do all
gastropods and bivalves have one?.  I suspect that cones and cowries
never do.
About Opercula - these little doors are clearly for defense and possibly
also to prevent dehydration in the case of exposure.  Any other uses?
In families where the operculum is present, is it present in all
species? For example, do all trochids and turbinids have opercula?
And Happy birthday to Conch-L!  What an excellent resource for beginners
like me.  I feel like I have a few E-friends now!  I know that some
members get impatient with the same "newbie" questions every so often as
more beginners find the site, but I'd really like to express my
gratitude to people like Tom Eichhorst, Paul Monfils, Gary Rosenberg,
Andrew Rindsberg and numerous others (I don't mean to leave anyone out -
there have been so many people) who always try and help us beginners
out.  It is expensive to get all the books one needs all at once, even
if one knew which ones those are.  I am starting to get my books, and
using the net and libraries also, so hopefully eventually I'll be able
to contribute more and ask questions less.  Thanks again for a great
site!