THE COMPARATIVE DISTRIBUTION OF TWO CHROMATOPHOROTROPIC HORMONES (CDH AND CBLH) IN CRUSTACEAN NERVOUS SYSTEMS

¹ Department of Zoology, Northwestern University, Evanston, Ill., and Marine Biological Laboratory, Woods Hole, Mass.

1. A survey was made of the effects upon Crago color-change of sea-water extracts of various parts of the central nervous system of thirteen species of higher crustaceans. The crustaceans represented the groups Isopoda, Natantia, Astacura, Anomura, and Brachyura.

2. Extracts of various portions of the nervous system among the various groups showed wide differences in their total chromatophorotropic activities, producing various degrees of telson and uropod darkening and of body-lightening and darkening.

3. An analysis of the results gave support to the hypothesis that most crustacean nervous systems possess at least two principles, a) a Crago body-lightening principle, CBLH, lightening all portions of the body except telson and uropods, and b) a Crago-darkening hormone, CDH, darkening the telson and uropods, and, in the absence of CBLH, the body as well.

4. CBLH is more or less uniformly distributed throughout the nervous systems of all the species examined except the astacurans in which it is demonstrated only for the circumoesophageal connectives and thoracic cord.

5. CDH is restricted to the circumoesophageal connective region of the Natantia, is differentially distributed throughout the nervous systems of anomurans, with highest concentration in the posterior region of the thoracic cord, and is distributed throughout the nervous systems of the other species except the brachyurans in which it is absent.