Ok I realize there is no one answer to this question because species vary so widely. At what point can a cypraea be termed adult? My query is general but to point out a specific species, dealers offer  a variety of sizes of Cypraea guttata. What do you look at to determine that the shell is mature. Thanks
Gary
Hi Gary. All shells vary in size to a greater or lesser degree, some enormously. Sometimes tiny ones are sold as 'rare dwarf variety', big ones as 'giants'. A cowry is fully mature when the lips are fully calloused over and the teeth are fully developed. The spire is also calloused over in most species. You can always tell an immature or juvenile cowry as it is a lot lighter in weight than a fully mature adult of the same species, also the colour pattern is frequently very different in juveniles. This led to a lot of synonyms in the 18th and 19th centuries when immature specimens were described as ful species.I think Felix Lorenz's book and website has photos of immature cowries.
Hope this has helped,
Dave Â