THE SPINY LOBSTER OF SOUTHERN FLORIDA. 303 



lost before molting have been regenerated. The new shell is soft to the touch, and all 

 of the spines can be bent. 



The spiny lobster remains near the cast-off shell for a short time unless disturbed 

 and then seeks shelter. The belief among the fishermen that the newly molted spiny 

 lobster eats part of the old shell has been verified by observation, but also spiny lobsters 

 which have hard shells have been observed eating such material when other food was 

 scarce. 



HARDENING OF THE NEW SHELL. 



The time required for hardening of the new shell varies considerably with individuals. 

 The shell does not harden appreciably for 24 hours after molting, but by the end of the 

 second or third day the mandibles, legs, claws, spines, and branchial regions of the 

 carapace have hardened sufficiently to have rigidity, and in four or five days the shell 

 has a papery firmness. The shell can not be dented easily after 14 days. One spiny 

 lobster was impounded without other sources of lime than the cast-off shell, and it was 

 observed that the new shell hardened after 18 days to the extent that it could not be 

 easily dented. 



AUTOTOMY. 



Autotomy has been observed to take place among spiny lobsters lying in the bottom 

 of a boat, the third pair of maxillipeds and first pair of legs being lost more frequently 

 than the other appendages. Autotomy, or reflex amputation, occurs along definite lines 

 where the tissues are probably prepared to check bleeding. This provision of nature 

 undoubtedly saves the life of the spiny lobster, for it has been observed that when a leg 

 is broken off at any other place than that where autotomy occurs bleeding is usually 

 unchecked, and such an injury often proves fatal. The plane of fracture when autotomy 

 occurs is between the coxa and basis, and if a leg is broken off at any other place the 

 remaining part is cast off at this plane. The legs of very large males often drop 

 off while the body is temporarily suspended, and it has been observed that autotomy 

 occurs when a spiny lobster comes into contact with certain objects, such as a sun-heated 

 plank or tin bucket. The flagellar of the antennae break off at their bases when an 

 attempt is made to pick up the spiny lobster by the antennae. 



REGENERATION. 



The completeness of regeneration of lost appendages depends upon how long 

 before the next molt they were broken off. It has been observed that legs lost six 

 months or more before molting are regenerated to about two-thirds their normal length, 

 but if a leg is lost a month or less before molting regeneration is very incomplete and 

 the appendage is represented by a small papilla. One female was observed which had 

 lost the dactyl of the fifth leg two months before molting. This segment was replaced at 

 the next molt by a budlike papilla. 



It has been observed that the flagellum of a broken antenna is regenerated some- 

 times before the next molt by the outgrowth from the stump of a small, soft flagellum. 

 This form of regeneration of the antenna has been observed infrequently. Regenerated 

 appendages are always smaller than the originals and are usually malformed, but they 

 gradually approach perfection of size and shape in succeeding molts. Broken places in 

 the shell, if they have not proved fatal, are poorly mended after molting, and holes 



