CHAPTER XI, 



HERMIT-CRABS. 



There was another animal present on " Rat Island,'* 

 as also on its larger neighbour, whose habits and evolu- 

 tionary history interested us greatty. This was the hermit- 

 crab (Cenobita diogeiies), and it swarmed ever^^ where in 

 its thousands. It was so common, indeed, that one day, 

 when we wanted some bait to go fishing, two of the sailors, 

 who had landed with bare feet, and so could not wander 

 more than a few yards from the beach in search of them, 

 filled a bucket, in less than no time, with these interesting 

 land-crabs, which have become so strangely modified 

 from the more ordinary type to suit the conditions under 

 which they now exist. 



This common West Indian hermit-crab belongs to a 

 genus (Cenobita) in which is included all those hermit- 

 crabs which have left the sea and taken to a life on shore ; 

 but have not been able, like the robber-crab (Birgus), to 

 dispense with some form of sea-shell, which they are 

 accustomed to appropriate for the sake of sheltering and 

 protecting their soft and fleshy abdominal parts. This 

 flabby-looking portion of the body is covered with a soft 

 flexible skin, strangely different from the hard chitinous 

 investment seen in corresponding parts of other 

 Crustacea. It is spirally twisted to the right to 

 correspond with the right-handed turns of an ordinary 

 gasteropod shell. 



Into this shell, which the crab either found empty, or 

 from which it ejected the rightful mollusc owner, this 



