CEABS. 237 



'^ A young white specimen of the Common Crab was sub- 

 jected to observation on the 29th of September. The body 

 might have been circumscribed in a circle three-quarters of 

 an inch in diameter, and the extended limbs by one and a 

 half inch in diameter. Its first exuviation ensued on the 

 8th of November, the second on the 30th of April following, 

 and the shell then produced subsisted till the 12th of Sep- 

 tember, when another exuviation took place, introducing a 

 new shell of such transparent white that the interior almost 

 shone through it. All the shells were white, and increased 

 somewhat in size successively. This last shell, of the 12th 

 of September, subsisted until the 29th of March, being a 

 hundred and ninety-seven days, when it was thrown off 

 during another exuviation. But what was remarkable, the 

 animal now had only the two large claws ; the other eight 

 limbs were deficient. Besting on its breast as it was, I did 

 not at first discover the fact that the creature presented a 

 strange and very unusual aspect. However, it fed readily and 

 proved very tame though helpless ; often falling on its back, 

 and not being able to recover itself, from the deficiency of 

 its limbs. I preserved this mutilated object with uncommon 

 care, watching it almost incessantly day and night ; expecting 

 another exuviation, which might be attended with interesting 



