NOTE ON THE HELIOTKOPISM OF PAL/EMONETES. 25 



On returning negative individuals to the undiluted sea water 

 they at once swam to the light side of the dish, but without 

 changing their orientation, i. e., with head directed away from 

 the light. 



The question of nomenclature which these observations sug- 

 gest may well await further investigations. The experiments 

 here recorded were made at the Marine Biological Laboratory at 

 Woods Hole. 



PHYSIOLOGICAL LABORATORY, 

 ST. Louis UNIVERSITY. 



