Well, "luna" is Latin for "moon", and Luna was the Roman goddess of the moon. A few shells come to mind whose scientific names incorporate that word, in a variety of ways. The genus Lunatia (family Naticidae), one of the "moon snail" genera, is a group of smooth, globular shells, presumably named for their resemblance to a full moon. The genus Lunella (Turbinidae), meaning "little moon", is a group of small, round, mostly smooth turban shells. In Australia there is a marine mussel (family Mytilidae) called Ciboticola lunata. This is a crescent-shaped shell, resembling the crescent moon or "new moon". Interestingly, the inner (concave) curve of its shell precisely matches the convex curvature of the ark shell Anadara (Scapharca) pilula, which is its usual place of attachment. In the little columbellid snail Mitrella lunata, the name refers to the markings rather than the shape of the shell. It is a dark shell with light crescent-shaped markings. Of course, we have english words derived from that Latin word too, including lunar, and lunatic, meaning one who is "moon-struck". Paul M.