We strike again. This is certain to sound obvious. But I have not seen it discussed. It seems that smooth, streamlined shells (Olives, Cowries, etc.) are more apt to spend a good part of their lives submerged under a layer of mud or sand than are shells with stickers on them (M. pecten, Lambis, etc.) Smoothies can submerge easier. Stickers allow for more protection out in the open. So the question is: are there exceptions to this phenomenon? Art