Hadley, Behavior of the American Lobster, 233 



the larvae swam about at random on the window side of the jar. 

 When orange glass was substituted for red, half of them came to 

 the room side of the jar. In the case of green glass, a few more 

 reacted negatively, and when blue glass was substituted for green, 

 all but five larvae gave a negative response. These five did not 

 manifest a definite positive reaction, but swam at random on the 

 window side of the jar. When the colored glasses were removed 

 and the larvae were submitted to the influence of diffuse daylight 

 through the small window, all reacted negatively. 



Case 2 — August 4, 9 a.m. Twenty ninth-day, third-stage lar- 

 vae were taken from one of the hatching bags and placed in the 

 dark box. Stimulation by the colored light resulted as follows : 



Color. Positive. Negative. 



Red 6 14 



Orange 3 17 



Green 2 18 



Blue 2 18 



White o 20 



Daylight o 20 



Case 3 — In the present case it was attempted to learn whether 

 the sign of the photopathic reaction in the larvae of this stage cor- 

 responds to the sign of their phototactic reaction. To this end, 

 ten ninth-day, third-stage larvae, fresh from the hatching bag, 

 were placed in the glass-bottomed box B, which was set over the 

 light-shaft and mounted upon colored glass plates. After each 

 observation either a period of five minutes was allowed for a uni- 

 form distribution of the larvae to take place, or the box itself was 

 reversed, leaving the glass plates in the same order. In other 

 instances the order of the glass plates was changed. During this 

 experiment the water in the box was eighteen to twenty mm. deep. 

 The results are presented below: 



Red. Orange. Green. Blue. 



4 o I ' 5 



I ' o 2 7 



Red. Orange. Blue. Green. 



^ -i 34 



II 44 



Red. Blue. Green. Orange. 



^ ^ 3 3 



Blue. Red. Green. Orange. 



60 31 



51 22 



