AN EXPERIMENTAL STUDY OF THE BEHAVIOR 

 OF AMPHIPODS WITH RESPECT TO LIGHT IN- 

 TENSITY, DIRECTION OF RAYS AND 

 METABOLISM. 



C. F. PHIPPS. 



I. Introduction 210 



A. Methods 210 



II. Responses of Untreated Amphipods to Light Intensity and to Direction of 



Rays 213 



III. Responses of Treated Amphipods to Light Intensity and to Direction of 



Rays 216 



A. Potassium Cyanide 216 



B. Chloretone 216 



C. Starvation 217 



D. Low Oxygen Content 217 



IV. Sides of the Experimental Tank, in Relation to the Lamp, occupied by the 



Amphipods 219 



V. Conclusions and Discussion 220 



A . Summary 220 



B. Metabolism, Physiological States and Reactions 221 



Bibliography 222 



I. Introduction. 



The object of this study was to determine the effect of reagents 

 and conditions affecting metabolism upon the reactions of am- 

 phipods to intensity and direction of light rays. The reagents 

 and treatments used were potassium cyanide, chloretone, star- 

 vation and lowered oxygen content. All experiments were per- 

 formed in the laboratory either upon amphipods just brought in, 

 or upon those kept in captivity from one to ten weeks. 



Three species of amphipods found in the vicinity of Chicago 

 were used in the experiments, namely, a swift stream species, 

 Gammarus jaciatus (Say) ; a sluggish river and lake species, 

 Hyalella knickerbockeri (Bate) ; and a pond species, Eucran- 

 gonyx gracilis (Smith). 



{A) Methods. — In all the experiments a dark room was used. 

 The special apparatus was a light grader, designed and first used 

 by Yerkes ('02) and described with diagrams by Mast ('11, p. 61) 



210 



