294 LIST OF ENTOMOLOGICAL WORKS. 



will undertake it ; aided by the labours of Desmarest, Audouin, 

 Milne, Edwards, and other continental writers — and with his 

 own great knowledge, derived from real observation, there is 

 no man living so competent to the task. 



Long after the Decapods have relinquished their prepa- 

 ratory form, and assumed that in which they reach perfection, 

 they have yet to undergo a repeated and complete ecdysis, the 

 mode of which appeared to vary considerably in different 

 orders. In a common lobster, which Mr. Newman has shown 

 us, destroyed while in the very act of casting its shell, the 

 cephalothorax, or principal shell, is parted longitudinally 

 down the back, and one half appears ready to fall each way. 

 In the spider-crab Mr. Hill describes the moult thus : — 



A few clays since a spider-crab was sent alive to me, taken in 

 the act of changing its coat. The operation was singular. The 

 upper and lower shell being parted, the legs were withdrawn from 

 their old cases, and served as a lever to detach the under shell from 

 the upper. Some exertion of the legs was necessary to raise the 

 upper shell : this had been accomplished, but it was not entirely 

 detached from the body when brought to me. The body was quite 

 soft, and the new skin of about the consistence of parchment. — 

 Magazine of Natural History, Vol. VIII. p. 468. 



We will now proceed to a statement of the Rev. Mr. Bree's, 

 a writer, whose veracity is beyond doubt; and we find that, 

 touching the question of metamorphosis considered as the 

 decided change of shape, we have in the common fresh- water 

 cray-fish, (Astacifs fluviatilis) an exception to the general rule. 

 The first passage quoted refers to the ecdysis of cray-fish, after 

 having attained a considerable magnitude. 



On these occasions, I well recollect, we seldom failed to find first 

 the exuvice, or cast shells, of the cray-fish ; 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 cray-fish came to be dressed, and served up at 

 table, it was no unusual occurrence to meet with som.e which had so 

 nearly approached the period of their change, that on breaking the 

 outward shell, a second and newly-formed shell Avas perceptible 

 beneath it. Fourthly, and to crown all, 1 have more than once seen 



