LIST OF ENTOMOLOGICAL WORKS. 299 



are divided longitudinally, at a suture which separates during the 

 operation, but which is not visible in the living animal. — Kirby, 

 on the History, &c. Vol. II. p. 52. 



The time requisite for hardening the newly - acquired crust, 

 according to its previous state, is from one to three days. Those 

 animals which are ready to moult, have always two strong sub- 

 stances, called crabs' eyes, placed in the stomach, which, from the 

 experiments of Reaumur and others, appear destined to furnish the 

 matter, or a portion of it, of which the shell is formed ; for if the 

 animal is opened the day after its moult, when the shell is only 

 half-hardened, these substances are found only half diminished ; 

 and if opened later, they are proportionably smaller. Thus has 

 Creative Wisdom provided means for the prompt consolidation of the 

 crust of these creatures, so that it is soon rescued from the dangers 

 to which, in its naked state, it is exposed. — Ibid. Vol. II. p. 55. 



With this doctrine we scarcely agree ; it has always 

 appeared to us, that the stomach is the least likely part of the 

 animal to contain the matter for the future shell ; and we 

 confess we are unable to devise a process by which the mass 

 of calcareous matter contained in these substances shall be 

 conveyed through the flesh to the external skin. The repro- 

 duction of lost members in Crustacea is a most interesting 

 subject, and one which claimed the close attention of Reaumur. 

 Mr. Kirby, quoting that high authority on this subject, gives 

 us the following account: — 



When a leg is mutilated in the summer, if examined a day or 

 two after the experiment, the first circumstance observable is a kind 

 of covering membrane, of a reddish hue ; in five or six days more 

 this membrane becomes convex ; next it is protruded into a conical 

 shape, and keeps gradually lengthening as the germinating leg is 

 developed ; at last the membrane is ruptured, and the leg appears 

 at first soft, but in a few days it becomes as hard as the old one. It 

 now wants only size and length, and these it acquires in time, and 

 at every moult it augments in a more rapid proportion than the legs 

 which have their proper size. The antennae, maxillae, &c. are 

 reproduced in the same manner ; but if the tail is mutilated it is 

 never reproduced, and the animal dies. — Ibid. Vol. II. p. 57. 



It seems to us unaccountable, that Crustaceology, one of 

 the most interesting branches of Entomology, should have so 

 few students in comparison with the other branches of the 



