The majority of ganglion cells in the retina of goldfish have receptive fields organized so that the cells respond particularly to simultaneous contrasts of color. The receptive fields are concentrically arranged. If the cell is excited by red light in the center, then it will also be excited by green light in the periphery, and inhibited by green light in the center or red light in the periphery. The occurrence of this arrangement and the reverse is about equal. The receptive field is much larger than had previously been thought.