So when a Cypraea's mantle is exposed, is the animal then completely, or nearly completely, outside of the shell? And also when it withdraws, can it tuck all of it's soft parts inside the safety of the shell? Nancy Conchologists of America List <[log in to unmask]> wrote: > I have never read why, but when you look at a cowry with expanded mantle, and considering the animal is going completely (at least in the species I observed), then one may think the teeth guide the mantle and the animal to withdraw perfectly in this tiny hole. Probably there are cells in the mantle that detect the correct teeth, so very quickly it can withdraw in the correct way, better than if there were no teeth. Note: Ovulids most often do not have the teeth, but frankly I think Ovulids do not withdraw the animal often. But also most Trivia and Erato have them. Other ideas ? Guido