Compound Ocellus of a Starfish: Its Function

Science  08 Jul 1966:
Vol. 153, Issue 3732, pp. 197-198
DOI: 10.1126/science.153.3732.197


The relative effect of light in inducing downward movements of the tips of isolated arms of Asterias amurensis is maximal at 485 millimicrons when the compound ocellus is intact; at 504 millimicrons when the ocellus has been removed. This finding suggests the coexistence of two photoreceptive systems, ocellar and nonocellar.