Hadley, Behavior of the American Lobster. 



219 



tests mentioned below, the light from the room and the light through 

 the shaft were cut off in order that a scattering of the larvae through 

 the box might occur. In other cases the position of the box was 

 reversed; and in still others both the position of the box and the 

 order of glass slides, changed. The Yesults of four tests are as 

 follows (the arrow represents the direction of the light entering 

 the end window of the box) : 



Case J — In this instance the red and orange glass plates were 

 removed and black paper substituted. The photopathic reaction 

 was found to be definitely positive, the young larvae grouping in 

 the blue area. Now, as before, the window at the end of the box 

 corresponding to that overlying the black paper was opened to the 

 subdued light of the room, while brilliant daylight entered the 

 blue end of the box. As will be observed, the conditions of this 

 experiment are similar to those of Experiment 11, save that, in 

 this instance, a greater difference between the intensity of light at 

 opposite ends of the box existed. Between tests the light from 

 both sources was cut off and the larvae were allowed to scatter. 

 The results, which may receive the same interpretation as those 

 of Experiment 11, are tabulated below (the arrow indicates the 

 direction of light entering the end window of the box); 



