4-68 Moulting of Crustaceans. 



merit : in fact, the change was almost completed. — Walter 

 Henri/ Hill. Soutkminster Vicarage, Essex, Feb. 12. 1835. 



[Ecdysis and transformation are not identical subjects, but 

 so kindred that the investigation of cases of ecdysis must con- 

 tribute to solve the question of transformation. The notice 

 of the preceding case had been written, its date shows, pre- 

 viously to Mr. Westwood's notification, in p. 275., of the doubt 

 extant on the condition of transformation appertaining to crus- 

 taceous animals, as Mr. J. V. Thompson has asserted it to 

 do. The following communication embraces both subjects.] 



{Ecdysis, or the Casting of the Skin or Shell, in Crustaceous 

 AnimalsJ] — In Mr. Westwood's remarks on certain species 

 of crustaceous animals, I perceive that some doubt is expressed 

 (p. 275.) whether crabs and lobsters do, in fact, periodically 

 cast their shells. " It is a point of some interest," says Mr. 

 Westwood, " as to the manner in which the shells of crabs 

 and lobsters are periodically cast, if, indeed, such be the case," 

 &c. I cannot speak with any certainty as to marine Crustacea, 

 but that the common freshwater crayfish occasionally casts 

 its shell, I can state from actual and repeated experience. In 

 my youthful days I was acquainted with a delightful, little, 

 clear, rapid brook, which meandered through a moist, boggy 

 wood, and abounded with trout and crayfish. To this brook 

 I was in the habit of paying a visit regularly once or twice 

 every summer. In my own defence, and as some apology for 

 my poaching unsportsmanlike propensities, I must observe 

 that the dense impervious character of the wood utterly pre- 

 cluded all possibility of using the angle rod ; so there was 

 nothing left for it, but to walk up the stream, and grope for 

 the game by hand in the holes, and under the hollow banks. 

 The produce of the day's work was generally a good dish of 

 crayfish, and of excellent, though not large, trout. On these 

 occasions, I well recollect, we seldom failed to find, first, the 

 exuviae, or cast shells, of the crayfish ; secondly, certain cray- 

 fish which had so lately undergone the operation, that their 

 new shells had not yet acquired their usual firm consistency, 

 but were soft and flabby, and as pliable to the touch as a piece 

 of thin parchment. These soft-shelled individuals we used 

 to consider as out of season, and we generally refrained from 

 taking them. Thirdly, I may state, that when the crayfish 

 came to be dressed and served up at table, it was no unusual 

 occurrence to meet with some which had so nearly approached 

 the period of their change, that on breaking the outward shell, 

 a second and newly formed shell was perceptible beneath it. 

 Fourthly, and to crown all, I have more than once seen cray- 

 fish in the act of casting their shells, i. e. with the old shell 



