Abstract
Abstract The distal retinal pigment in the fiddler crab, Uca pugilator, displays a circadian rhythm in constant darkness. The pigment approaches the fully light adapted position by day and the fully dark adapted position by night. This rhythm is presumably due at least to rhythmical release by day of a distal retinal pigment light‐adapting hormone. Extracts of eyestalks from Uca produce a light‐adaptational response in the crab, but extracts of eyestalks from the prawn, Palaemonetes vulgaris, do not produce a light‐adaptational response in the crab, but a dark‐adaptational response instead. In contrast, both types of extract produce a light‐adaptational response of the distal retinal pigment in Palaemonetes. The possibility of a species specificity in the action of distal retinal pigment light‐adapting hormones in crustaceans is discussed.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
