Abstract
1. The organization of central and peripheral responses for one type of spike-producing cell in the retina of the turtle (Pseudemys scripta elegans) has been studied. These cells produced a short burst of spikes following the onset and offset of a small spot of illumination (i.e. ON—OFF cells). The effect of increasing the area of illumination was to include a peripheral inhibition. Intracellular ON and OFF responses were, however, affected differently.