MOLTING AND CYCLIC ACTIVITY IN CHROMATOPHOROTROPINS OF THE CENTRAL NERVOUS SYSTEM OF THE BARNACLE, BALANUS EBURNEUS

¹ Duke University Marine Laboratory, Beaufort, North Carolina

1. The central nervous system of the barnacle, Balanus eburneus, was removed at known intervals following ecdysis, extracted in sea water, and assayed by injecting into eyestalkless U ca pugilator to determine if the barnacle chromatophorotropins exhibited a cyclic activity associated with molting.

2. A cyclic pattern of activity was observed within one intermolt period. The changes in activity of the U ca black-pigment-dispersing substance, highly significant at the 95% level, were the low concentrations immediately following molting and 48 hours after ecdysis and the high concentration which occurred at 24 hours after molting. In barnacles which did not molt again within the usual 72-96-hour period following the first molt, the level of activity of the central nervous system extracts remained low. Body weight and the activity of the central nervous system extracts were found to be independent.

3. The hypothesis is presented that in the absence of a storage organ comparable to the sinus gland of Brachyura, neurosecretory products originating from the central nervous system are released directly into the blood. The release of these products following the period of greatest concentration, 24 hours after molting, stimulates the physiological processes and cellular changes which culminate in ecdysis.