Paul,
 
I have also read the shell underfoot story (but is was a gloriamaris).
It is like the rice paper Epitonium scalare - great story but.....
 
As for your expensive Cypraea teulerei.  I saw some in a rock shop in
Tucson many years ago for something like $5.00 a piece.  Even with no
data, I figured this was an unbelievable opportunity.  Needless to say, I
hadn't realized the price had dropped and ended up with three nice
looking shells with no data that were worth just what I paid.  This game
is full of great stories.  A favorite, old (1936) book of mine is
"Strange Sea Shells and Their Stories," by A. Hyatt Verrill.  The author
uses only common names so it is sometimes a bit difficult to figure out
which shell is really being discussed, but it is still a treasure.  The
stories include some good, if dated natural history, but what is really
neat are the references to: the only one dozen glory-of-the-seas known to
exist, or the fifty specimens of spotted cowry (Cypraea guttata), or the
$200.00 Epitonium scalare, and last a story about a fisherman who spotted
what he thought were gloriamaris and gathered up about 20 or so only to
be found dead later on from the stings of "cloth-of-golds" (Conus textile
- I presume).  Great stuff.  The sort of stuff that if it isn't true, it
ought to be.
 
Tom Eichhorst in New Mexico