76 INLAND FISHERIES. 



first ring of the tail. This is a characteristic of the fifth and sixth 

 stag-es, possibly the seventh stag-e also, and it is quite certain that 

 some of the specimens had shed their skin twice as many times 

 as others of the same ag-e. This variation is shown in two lobsters 

 taken out of the cars on October 17th. (See fig-ure 9.) 



This marked variation in the rate of g-rowth is the same i^he- 

 nomenon which has been repeatedly demonstrated in the growth 

 of star-fishes and clams, and makes it impossible to say that a 

 specimen will reach a certain size in a g-iven leng-th of time. In 

 the case of the star -fish and clam the variation has been shown to 

 depend on the food supply, and it is probable that the same is 

 true of the lobster. Althoug-h, apparently, the conditions were 

 the same for all the lobsters in a certain car, there are many possi- 

 bilities of difi'erent conditions. The lobsters have a strong in- 

 dividuality, and the activities of difi'erent individuals vary to such 

 an extent that it is not strange that some are more successful in 

 obtaining food than others. If, by the same good fortune, a certain 

 lobster obtained an advantage at first, this advantage would in- 

 crease as time went on, since in lobster society the stronger indi- 

 viduals constantly menace the weaker ones. 



These peculiarities make themselves evident at once when a 

 number of lobsters are placed under observation in a small space. 

 I recall one instance in which a certain lobster took for his head- 

 quarters the cork which plugged the hole in the bottom of the 

 aquarium. For nearly a week (and until he was killed in a fight) 

 he kept a lookout from the top of this cork or hid in its shadow, 

 occasionally making excursions about the aquarium, but always 

 returning again to the same spot. 



In order to keep some of the specimens over winter, they were 

 placed in a car which was covered and sunk in the channel. They 

 were alive on December 22, and it is hoped that some of the speci- 

 mens can be carried over to the next season. 



The following tables present in a condensed form the main re- 

 sults of the experiments in lobster culture at AVickford. 



The first four photographs represent the first four stages in the 



