Hadley, Behavior of the American Lobster. 



245 



into it. In an earlier paper (Hadley 1906b), the writer has 

 assumed this to be a true phototactic response. One other instance 

 which appears to support this view may be recorded as follows. 



Case 6 — Ten sixteenth-day, fourth-stage lobsters were placed 

 in a large slender dish, which was set in the dark box. The larvae 

 manifested no tendency to undergo either body-orientation or pro- 

 gressive orientation. Next, the same lobsters were placed in the 

 glass-bottomed box, now lined with white paper, which greatly 

 intensified the light within. This box was put with the end win- 

 dow toward the bright sunlight, and the records of five trials (ten 

 larvae in each) indicated that, when the light was sufficiently 

 intense, the early fourth-stage lobsters might give a positive photo- 

 tactic reaction. In this instance twenty-six larvae were positive, 

 twelve negative, and twelve neutral. 



When the white paper was removed, and four more tests were 

 made, the results showed that twenty-five larvae were negative, 

 six positive, and nine neutral. 



Experiment 2y Reaction of mid-fourth-stage lobsters. Case 

 I. Phototactic reaction — August 10, 3:30 p.m. Ten mid-fourth- 

 stage lobsters were transferred from the hatching bags to box B, 

 and the experiment was continued in daylight as in Experiment 

 24, Case 2. The results show a definite negative phototactic 

 reaction, and may be tabulated as follows (similar results were 

 obtained when a white lining in the box was used, though in this 

 case, they showed a less definitely negative reaction) : 



