834 Crustacea. 



Exuviation of the common Craw-fish (Palinurus vulgaris).* 

 By E. Chirgwin, Esq. 



Two instances have been recently witnessed of what may be called 

 the moulting of the common craw-fish, differing in some respects 

 from the manner in which it is said to take place ; I think it may be 

 interesting to state the circumstance as it really happened. Two 

 years since, in the month of July, one was taken in a trammel net, 

 and being disentangled, and held up in the hand by its antennae, a 

 sensible shudder was given by the creature ; immediately after which, 

 it dropped from its shell to the bottom of the boat, leaving its old 

 covering in the hand of its surprised captor, unseparated in any part, 

 and not a joint broken. In August last another was caught in a 

 similar way, and also cast its shell on board the boat. In this 

 instance, as in the former, nothing called attention till after the shell 

 had fallen off, when it appeared that the carapace had been lifted, 

 and was nearly separated from the tail or flap. The new animal was 

 lively and strong, and might be handled by its antennae, but it was 

 sensible of the slightest touch on any part of the body, w r hich was 

 evinced by its uttering a loud cry, as if in pain. During these months 

 I have taken the craw-fish before the moulting has taken place, and 

 this membrane has been so tough that it could hardly be torn by 

 hard twisting. At this time they are unfit for food, but in a very short 

 time, even when the new shell has not acquired a calcareous state, I 

 consider them in the highest condition. It would seem, therefore, 

 that it is during these months that the long-tailed crustaceans moult, 

 but from finding the exuviae of other kinds at other seasons of the 

 year, that the different kinds vary a good deal in this respect. Unless, 

 therefore, the casting of their shells in these two instances can be 

 supposed to have been caused or accelerated by the situation and 

 attendant circumstances in which the fish were found, it is evident 

 that no softening or splitting of the shell, or divisions of the joints 

 take place, to enable the animal to extricate itself. 



Edward Chirgwin. 



Newlyn. 



[The observations of practical men on any branch of Natural 

 History arc always valuable, inasmuch as they are not distorted by 



* Head hefore the Natural-History Society of Penzance. 



