194 



REPORT OF COMMISSIONERS OF IXLAXD FISHERIES. 



Influence of Hunger in "Burrowing". — On August 5, about thirty 

 early fourth-stage larvae were taken from one of the confinement 

 bags. They did not show much evidence of hunger, and were there- 

 fore isolated for forty-eight hours without food. At the expiration 

 of this' time they all proved to be very hungry. Now two groups of 

 five lobsters each were taken from this lot and each group was 

 placed in a 14 centimeter crystallization dish, the bottom of which 

 was covered with sand, gravel, and shells. Immediately after this 

 one group of lobsters was fed with chopped clam meat, while the 

 other group was left hungry. The dishes were placed on the labora- 

 tory table, and records were taken frequently to determine when, 

 the burrowing would be first manifested, and in which group. For 

 some little time both groups swam more or less constantly near the 

 surface. Further records may be presented as follows : 



Group Unfed. 



Aug. 7. 10 A. M I 1 larva burrowed. 



7, 11.30 A. M j 2 larvs 



7, 3.30 P. M 3 •' 



9, 9 A. M 4 " 



9. 9 A. M 4 " 



6, 6 P. M 4 " " . 



5 larvae swimming or crawling. 



5 " 



5 •• 



*At this point one of the five lobsters was killed and eaten by the others, three of which 

 immediately burrowed. 



These results appear to show that while hunger may postpone the 

 liberation of the burrowing instinct, satiety appears to favor its 

 early appearance. One other experiment, the converse of the pre- 

 vious case, may be introduced: 



Influence of Food Stimulus upon Surface Swimming in the Fourth- 

 stage Larvae. — In this case about twenty larvse in the middle and late 

 fourth stage were placed in a 25 centimeter glass jar filled with salt 

 water to a depth of four inches. These lobsters were kept without 

 food until they showed evident signs of hunger. All the larvae re- 



