REPORT OF COMMISSIONERS OF INLAND FISHERIES. 129 



dominal segment appear as buds, and by the eighth stage have 

 developed sufficiently to enable the sex to be told. Beyond this 

 stage the changes consist merely in the gradual assumption of the 

 mature form and structure. 



11. Some Peculiar Means of Self-Preservation. 



Any one who has handled lobsters under 3 inches in length is 

 familiar with the fact that the little fellows, when handled, will 

 straighten out and to every appearance seem to be dead. The 

 rigidity does not cease immediately when replaced in the water. 

 This death-feigning habit is gradually outgrown, and perhaps is never 

 found among adult lobsters. It is supposed to be useful to the 

 animal in protecting itself against fishes which prefer live food. 



Autotomy, the voluntary shedding of an appendage, is another 

 habit which is more easily seen to be self-preservative. If a lobster's 

 claw is held too tightly or crushed, it is almost always quickly 

 dropped off. As it can again be regenerated the lobster is only 

 maimed for a short time, while the loss of the claw may prevent the 

 lobster from getting pulled out of its burrow and destroyed. 



12. Sensibility to Light. 



The adult lobster is negatively heliotropic, i. e., it will endeavor 

 to get away from the light. This is not, however, characteristic of 

 all stages. In the first three larval stages the fry seem to seek the 

 lighted area (positively heliotropic). The fourth stage also has this 

 peculiarity till near the end of the stage, when it seems to anticipate 

 the later stages and becomes negatively heliotropic* This negative 

 heliotropism is perhaps the explanation of the fact that at this time 

 also the lobster leaves the surface and begins to burrow at the bottom. 



It is an interesting fact, also, that the fry when confined in one 



*See article, Observations on Some Influences of Light upon the Larval and Early Adoles- 

 cent Stages of Homarus Americanus, by P. B. Hadley, in the Report of the Commissioners of 

 Inland Fisheries of the State of Rhode Island made to the General Assembly at its January 

 session, 1906. 



17 



