158 CRUSTACEANS, 



and a half. The old shell separated was quite pale ; the new one dark 

 green, without any white whatever. It is represented, fig. 3, as appear- 

 ing on April 13, having undergone no alteration from the date of exu- 

 viation on March 22. The creature again seemed dull on May 31st, 

 which was followed by another exuviation, being the fifth, during the 

 night of the first of June. In the new integument it appeared very con- 

 siderably enlarged in all its parts, the colour of the shell dark green, 

 whereon were some darker specks ; after the lapse of a fortnight the cast 

 shell attained a lighter reddish tinge than the colour of brick. 



The creature had become very tame. It continued feeding readily 

 on every kind of animal substance offered ; even half an Aphro- 

 dita, a very rough morsel, was devoured, and only some of the scales 

 rejected. It always came to the side of its glass prison, as if expecting 

 a supply from any one in the vicinity. During the day it shewed itself 

 desirous of reposing under any covering, and strained hard to get a large 

 flat shell into such a position as would afford protection. Night was 

 the season of greatest activity, which was succeeded by quiescence to- 

 wards morning. Then it would remain long crouching down in the 

 vessel, though always ready to be aroused by the presence of food. 



From various circumstances, it is obvious, that, although the animal 

 undergoes an extraordinary process in changing the integument, that the 

 impressions, in as far as they would be received in the old integument, 

 shew the habits acquired are not lost, but remain permanently. Some- 

 thing like memory or election is demonstrated. 



After the preceding specimen, which was a male, had been above 

 a year in my possession, another of little disparity in size, a female, was 

 introduced into the vessel along with it. 



All the animals of this species, large and small, of whatever age or 

 sex, in as far as I have observed, wage the fiercest war against each other, 

 whether from their contentious dispositions, or to satisfy their cannibal 

 appetites. Therefore, to guard against accidents, I took the precaution 

 of gorging both these creatures with food. But here it might have been 

 spared, for they were completely reconciled from the first moment ; 

 and shewed, by unequivocal symptoms, how agreeable a companion was 



