It may seem alien, but think about this the next time you enjoy a scallop or a clam: they might be looking back at you. Some species have tens of tiny eyes which line the edges of their characteristic shells. Unlike almost all other adult bivalves, scallops and clams can grow eyes which use a unique ‘mirror’ system to form images of their surroundings. A concave reflective layer, the argentea, sits close beneath the lens of the eye and reflects the image back to it – thus, reversing the image twice (once as it passes through the lens and once on the way back) and correcting it, unlike our own eyes.
Image courtesy of Robert Rath.