Exuviation in the Crustacea. 347 



wanting the limbs. I preserved this mutilated subject with 

 uncommon care, watching it almost incessantly day and 

 night; expecting another exuviation which might be attended 

 with interesting consequences, I felt much anxiety for its 

 survivance. My solicitude was not vain. After the defec- 

 tive shell had subsisted eighty-six days, its tenant meantime 

 feeding readily, the desired event took place in a new exuvi- 

 ation on June 23. 



What was now disclosed ? Still another animal, E, came 

 forth, and in the highest perfection, quite entire and symme- 

 trical, with all the ten limbs peculiar to its race, and of the 

 purest and most beautiful white. I could not contemplate 

 such a specimen of nature's energies restoring perfection, 

 and through a process so extraordinary, without admiration. 

 Something yet remained to be established — Was this per- 

 fection permanent, or was it only temporary I Like its pre- 

 cursor, this specimen, a very fine one, was quite tame, 

 healthy, and vigorous besides. In 102 days it underwent 

 exuviation, when the new animal, F, appeared in all per- 

 fection, with a shell of snowy white and a little red speckling 

 on the limbs. Finally, its shell having subsisted 189 days, 

 was succeeded by another, G, of equal beauty and perfection, 

 the speckling on the legs somewhat incre&,sed. As all the 

 shells had gradually augmented, so was this much larger 

 than any ; the limbs extended would have occupied a circle 

 of four inches diameter. About a month after this last ex- 

 uviation the animal perished accidentally, having been two 

 years and eight months under observation. This was a fine 

 and interesting specimen, extremely tame and tranquil, al- 

 ways coming to the side of the vessel as I approached, and 

 holding up its little claws as if supplicating food. Thus the 

 perfection regained is permanent ; nature preserves the sym- 

 metry she originally designed. 



A weaker specimen of the Cancer McenaSj H, had been mu- 

 tilated of both claws and six limbs by the preceding animal 

 when first taken. Crabs are in general extremely conten- 

 tious, many species waging a war, even to extermination, 

 against each other. This mutilated specimen survived several 

 weeks, and died apparently of abortive exuviation — not of its 



