Colour Changes in Hippolyte varians

Abstract

THE demonstration by Perkins¹ that colour changes in Palæmonetes vulgaris were controlled by a hormone that originated in the eye-stalks has since been confirmed and extended by a number of investigators (see Hänstrom's² review). Gamble and Keeble³ in their classic study of colour changes in Hippolyte were the first to describe a diurnal rhythm which persisted under constant environmental conditions. Within the past five years, several papers on persisting diurnal rhythms in the pigmentary system of crustaceans have appeared. The two English investigators interpreted the phenomena of crustacean metachrosis, according to the view of chromatophoral activity prevalent at that time, as being dependent upon the nervous system. We reinvestigated the colour changes of Hippolyte to see whether the endocrinal control similar to that found in other crustaceans was present.