246 Journal of Comparative Neurology and Psychology. 



Case 2. Photopathic reaction — August 9, 3:30 p.m. Ten 

 fourth-stage lobsters were removed from one of the confinement 

 bags and placed in 16 mm. of water in the glass-bottomed box. 

 The glass plates were arranged in the order given below, and tests 

 were made at five-minute intervals. The results, which showed 

 a diminished tendency to remain in the areas of greatest illumina- 

 tion, are represented in the following table: 



Red. 



Orange. 



Green. 

 I 



3 

 I 



4 



Blue. 

 4 

 3 



When, some hours later, the same lobsters were tested again 

 the results of five trials were as follows: Blue, 13; green, 9; orange, 

 7; red, 21; apparently in this instance it can not be said that the 

 mid-fourth-stage lobsters were either positively or negatively pho- 

 topathic. Yet the last instance shows a tendency toward a neg- 

 ative reaction. 



Experiment 26. Reaction of late fourth-stage lobsters. Case i. 

 Photopathic reaction — August 12, 2 p.m. Ten late fourth-stage 

 lobsters were transferred from one of the confinement bags (where 

 the majority had already entered the fifth stage) to the glass-bot- 

 tomed box which was placed over the light-shaft in order to test 

 the photopathic reaction. In this case nine consecutive tests were 

 made, three minutes being allowed for each orientation. The 

 results, which are characteristic of all other tests, and which show 

 a tendency on the part of the lobsters to avoid the light, may be 

 recorded as follows: 



