THE ROLE OF THE SINUS GLANDS IN RETINAL PIGMENT MIGRATION IN GRAPSOID CRABS

Abstract

The crabs Pachygrapsus and Hemigrapsus exhibit a diurnal cycle of activity of the retinal pigments in constant darkness, but not in constant illumination. Injections of extracts of sinus glands, optic ganglia, and other nervous tissues show that retinal pigment activating material is present in nervous tissue in concns. not higher than 1/20 of that occurring in sinus glands, but because of the relative bulk of nervous tissue, the total amount of active principle in optic ganglia is double that in the sinus gland. Operative removal of sinus glands reduces the extent of day-adaptation of crabs kept in darkness, while optic nerve damage produces day-adaptation. These observations are consistent with the view that the sinus gland represents a part of the nervous system specialized for the production and release of a factor which is also produced in and possibly released from strictly nervous tissues and active upon retinal pigments.