Abstract
Light emission of the small ophiuroid Amphipholis squamata was characterized; luminescence of whole animals and isolated arms were not significantly different: a monophasic response lasting 2 min. was observed in response to potassium chloride depolarizations. Among the various putative neuromediators tested, acetylcholine induced the light; since atropine but not tubocurarine inhibits the KCL luminescence of isolated arms, this result suggests that muscarinic receptors are involved in the nervous control of Amphipholis squamata luminescence.