Sexing snails

This reply is WAY OLD, as I have over 4,400 messages presently in my filing
cabinet, and am, (to put it mildly :-)) a bit behind in my reading. So - -
sorry if this proves to be redundant. (original message about January 16 !!) 

Snails are Hermaphroditic, as are earthworms.  IOW, each snail is both male
and female at the same time.  Fertilization is mutual, two snails exchanging
sperm simultaneously. Yes, they do store the sperm until needed. Yes, you can
set up deliberate crosses, line breeding, etc., by isolating the two snails
you wish to breed.  The eggs of both will be a cross of both. 

If you think that is confusing, check out Marine Clown fish!  <ggggg>