In your search for fossil Cypraea in Florida, you might like to
read a couple of items from many years back that were in the
HAWAIIAN SHELL NEWS. Both are about Cypraea problematica.
Try http://www.geocities.com/~makuabob/ and look for
New Series No. 163 -- July, 1973 -- VOL. XXI No. 7
and
New Series No. 175 -- July, 1974 -- VOL. XXII No. 7
Aloha,
makuabob (a.k.a. Bob Dayle)