EXUVIATION OF HERMIT-CRABS. 131 



exuviation. The result of my labours has not been 

 so satisfactory as I could wish, from my not having 

 been able to collect any ' sets ' of exuviae. I cannot, 

 therefore, speak with certainty as to the frequency of 

 this phenomena. By this time my readers will know 

 that the tail of the Hermit-Crab is very tender and 

 fleshy, being covered merely with an extremely deli- 

 cate membraneous skin, while the carapace, claws, 

 and antennae of the animal are protected by a hard 

 crust, similar to the Lobster, Cray-fish, &c. 



From this peculiar formation of the crab, I was 

 not at all surprised to find, on several occasions, the 

 upper part of its body alone cast off, and therefore 

 came to the very natural conclusion, that as the tail 

 was soft, it would grow and increase in proportion to 

 the other parts of the animal, without ever needing 

 the skin to be changed. 



Each morning and evening during the time my 

 experiments were being conducted, I examined all the 

 tanks attentively, to see whether an exuvium had 

 been cast. If visible, the object was picked out and 

 gummed in a box, and a date placed above it for 

 future reference. After having performed an opera- 

 tion of this kind one afternoon in October 1858, I 

 saw a Hermit-Crab (who had cast his shell on the 

 previous day) hurriedly leave his testaceous dwelling, 

 then scrape away at his tail, and after a moment's 

 interval, leap into his old seat again. On inspec- 

 tion, I found to my surprise that he had actually 



