The most interesting thing about the scallop is its
eyes. (You probably didn't know scallops even had eyes. Well, they do.) The eyes are very tiny, and occur along the curved edges of the shell, just inside, about one eye per shell corrugation. Each eye is rather remarkably like a certain kind of
reflecting telescope complete with a spherical mirror to reflect incoming light rays onto a
retina, after being corrected for
spherical aberration by passing through a lens whose shape is, incredibly, a
Cartesian oval.
I swear I'm not making this up. You can look it up yourself in Richard Dawkins's extremely interesting book, Climbing Mount Improbable