> P.S.  What kinds of snakes feed largely on land snails??

Since I also am involved with reptiles and this is shell related -- without
too much of a stretch, I thought I would answer.  There are actually several
snail eating snakes in the world, however, none in the US that I am aware
of.  However, just south of us in the Caribbean and in Central and South
America are members of the genus Dipsas (Colubrids) as well as a couple of
other less well known genera.  These snakes are very slender and are
specially adapted to prey upon snails.  They have a jaw arrangement unique
in snakes that allows them to grasp the shell and insert the lower jaw
(independent of the upper jaw) into the aperture, grab the snail with sharp,
recuved teeth and pull out their meal.  The only species I have actually
seen is Dipsas variegata from Ecuador -- a long, skinny, aboreal serpent.
There is a ground dwelling snail eater in west Mexico that looks somewhat
like our eastern kingsnakes (black with yellow crossbands).  There are also
several species (and even genera I believe) of snail eating snakes in Asia
and at least one in Africa.  The African snail eating snake is in a separate
family from the others and lacks the special jaw arrangement.  Instead, it
grabs the mollusk and bashes it around against a rock until the shell is
smashed and the animal can be eaten.    So there you have it.  The list of
mollusk predators is a lengthy one.

Tom Eichhorst in New Mexico, USA