Spectral Sensitivity of the Scallop Pecten maximus

Abstract

The spectral sensitivity of the scallop Pecten maximus was determined behavorially; the shadow reflex was used as the index of sensitivity. The photopic visibility curve displays two prominent peaks, one at approximately 480 mµ, and the other with wavelength maximum at approximately 540 mµ. Reduction of background illumination results in a great increase in sensitivity at 480 mµ relative to the 540-mµ peak. This suggests that the scallop may possess photoreceptors that behave like rods in vertebrates. sensitivity of this animal.