Hadley, Behavior of the Ainerican Lobster. 



243 



Case 5. Phototactic reaction — August 9, 3:40 p.m. Ten early 

 fourth-stage lobsters were transferred from the confining bag to 

 box B, and this was placed with the end toward the west light. 

 In this case, colored glass plates were placed at intervals in front 

 of the end window to modify the intensity of the light entering the 

 box. A five-minute intermission was allowed between observa- 

 tions. The results, which clearly establish a negative phototac- 

 tic reaction, are presented in the following table : 



Case ./. Phototactic reaction — In the following case, in w^hich 

 the same lobsters were used the source of illumination was the 

 acetylene light and the intensity of the light which entered the 

 end window^ of box B was modified in two ways: (i) by the col- 

 ored glass plates placed between the light and the window in the 

 end of the box; (2) by the distance of the light from the box. The 

 results, which demonstrate a definite negative phototaxis, were as 

 follow'S (in all cases the figure i indicates the division of the box 

 nearest the light; ^ the division farthest from the light) : 



