Unlike most bivalves, scallops contain a varying amount of simple eyes situated along the edge of their mantle and also have a well-developed nervous system. They have anywhere up to 200 eyes that line their mantle. These eyes are a brilliant blue color. While they cannot make out exact shapes, they allow the scallop to detect light, shadow, and motion. They use their retinas to focus light, similar to the cornea in human eyes.
