88 CRUSTACEA. 



attached, that the least touch causes them to shed them. In 

 hke manner, it is said that lobsters fear thunder, and are a|3t 

 to cast their claws on a great clap, and that they will do the 

 same on the firing of cannon ; so that when men-of-war 

 meet a lobster boat, a jocular threat is used, that if the 

 master does not sell good lobsters, they will salute him. In 

 the course of a day or two, the naked skin exposed by the 

 wound is found to be covered with a reddish pellicle, which 

 soon assumes a convex siu-face, grows longer, becomes 

 conical, increases in size, and splitting, exposes to \dew a 

 soft body, composed of the same number of parts as had 

 been lost. This soon gains the consistence of the remainder 

 of the body, but never acquires the size of the limb lost, 

 although, at every subsequent moulting of the skin, the size 

 increases more rapidly than that of the rest of the limbs. 



This curious phenomenon involves, in a singular manner, 

 the principles upon which the moulting of the annulosa 

 takes place. We are taught that the wings of a butter- 

 fly exist in the caterpillar state, and that the legs of the 

 larva of a grasshopper envelope the legs of the perfect 

 insect : if, therefore, we admit the theory of Swammerdam, 

 subsequently noticed, as regards the true insects, we shall 

 be compelled to establish another theory for the Crus- 

 tacea, similar to that of Dr. Herold, also subsequently men- 

 tioned. Reaumur has, indeed, attempted to explain the 

 causes of this reproduction of limbs ; inquiring, if, at the 

 base of each leg, there may not be a provision of new legs, 

 as in childi'en there is a tooth under the milk tooth ! I 

 am surprised that so acute a reasoner as Reaumur should 

 not have perceived the incorrectness of such a supposition. 

 It is perfectly natural that the milk-teeth are one day des- 

 tined to fall, and it is natvu'al that their places should be 

 occupied by fresh teeth, which are accordingly provided. 



