COLOUK OF THE CAST-OFF SHELLS. 127 



initiated, that the appearance of the above objects is 

 extremely pleasing ; for, as the exuvium becomes 

 dry, its colour changes to a bright scarlet, somewhat 

 resembling that which the crab assumes when placed 

 for a time in boiling water. 



The next series of specimens, five in number, 

 possess even still greater interest than the first ex- 

 amples. They were produced by a youthful (7. 

 Mcenas, at the following consecutive intervals : 



The first moult took place on llth April 1858 ; 

 the second on the 22d of May following; the third 

 on July the 3d ; the fourth on the 30th of August ; 

 and the fifth on the 26th of September in the same 

 year. So that between the first and second period 

 of exuviation there was an interval of forty-one days, 

 between the second and third forty-two days elapsed, 

 between the third and fourth fifty-eight days, but, 

 singular to state, between the fourth and fifth moult 

 only twenty -seven days intervened. 



My first impression was, that as the creature grew 

 older, its shell would be renewed less frequently, and 

 the dates of the sloughings seemed to support this 

 idea until the fourth moult. It had occurred to 

 me that perhaps the operation might be accelerated 

 by the amount of diet which the crab consumed. 

 In order to test this, I fed the animal carefully every 

 day, as though he were a prize beast about to be 

 exhibited at some Christmas show. Nothing loath, 

 he ate of everything that was placed before him with 



