HadleY, Behavior of the American Lobster. 251 



intense, while the end window of the box (at the red end) remained 

 open, as in the last experiment. The results, which demonstrate 

 that the phototactic reaction had still further overcome the photo- 

 pathic, were as follows: 



Blue. Green. Orange. Red. 



2242 

 1324 

 3232 



4321 

 i 3 2 3 



IS IS 'S IS 



In the last two instances it becomes apparent that the fifth- 

 stage lobsters, unlike the early-stage larvae, could not be forced, 

 by the directive influence of the light rays, into an area of greater 

 light-intensity. In other words, the tendency to manifest a nega- 

 tive phototactic reaction was not sufficiently strong to overcome 

 the tendency to give a negative photopathic response. 



{B.) Experiment 28. Phototaxisleadingtofatal results — Before 

 bringing to a close this consideration of the reactions to light in 

 lobsters of the fourth and fifth stages, it may be appropriate to 

 introduce the results of some experiments whose aim was to show 

 the extreme nature of some phototactic reactions. In other words, 

 attempt was made to determine whether or not the strong direc- 

 tive influence of the light rays could compel the larvae so to act 

 that they would do injury to themselves as in the familiar case of 

 the moth that flies into the flame, or of Ranatra, mentioned by 

 Holmes (1906). The reactions of the fourth-stage and fifth- 

 stage lobsters will be considered together. 



Case I. Fourth-stage lobsters — For this series of experiments 

 box B was set up as represented in Fig. 7, being supported at one 

 end so that the bottom of the box made an angle of about fifteen 

 degrees with the table. The box was filled with water so that 

 when it was slanted, the water-line did not quite reach the angle 

 made by the bottom and upper end, B. In this way there was 

 created an inclined plane, slanting from the window end. A, of the 

 box to the higher end, B. The water consequently diminished in 

 depth as the end, B, was approached. At this end there was an 

 inch or more of the bottom of the box not covered by water. The 

 light from the window, L, was reflected into the box by the mirror, 



