Image formation by a concave reflector in the eye of the scallop, Pecten maximus.

The eye of Pecten has been described histologically many times (see Patten, 1886; Dakin, 1910). There has, however, been no serious attempt to examine it as an optical system, nor to assess the nature and quality of the visual image that such an eye produces. Structurally, the eye possesses many features typical of the camera eyes of vertebrates, cephalopods, and some annelids, and most workers have assumed that the optical system was analogous to that of camera eyes, with a lens forming an image on a retina lining the back of the eye (Text-fig. 1).