332 HERMIT-CRABS. 



species was apparently different from, tbouo-h closely allied to, trie 

 common beach species, and frequented the shells of a land-snail 

 (Helix). I was indebted to Lieutenant Homing for directing my 

 attention to the hermit-crab, found 190O feet above the sea. It 

 appears to me likely that these hermit-crabs will be found at much 

 greater heights in this group, since, in this island, their ambition to 

 I'ise had carried them up as far as they could go. 



Other species of hermit-crabs, that are common in these islands, 

 belong to the genus Pagnriis. They are conspicuously distinguished 

 from the species of Coenobita, above described, by their first pair of 

 claws, which are small and weak and ill-adapted for defensive pur- 

 poses. For this reason, these species are less able to look aftei- 

 themselves ; and since they cannot form the operculum-like shield 

 with their claws at the mouth of the shell, tlrey always choose shells 

 \\diich will permit of their retiring well within it, so as to be out oi 

 the reach of their enemies. Some species are found in the stream- 

 courses and in the brackish water near their mouths, when they 

 often frequent cast-off Melania shells. Other species (?) yjrefer the 

 sea-water on the reef-flats. I noticed one individual that displayed 

 its eccentricity of disposition, in selecting, as its abode, the hollow 

 tube of a small water-logged stick, about six inches long, which it 

 di-agged about after it during its peregrinations, and into which it 

 retreated when alarmed. On one occasion, I observed a large 

 Dolnim shell, moving briskly about in a pool of salt-water, which, 

 on picking up, I found to be tenanted by a Pagitnis, so ridiculously 

 small, in comparison with the size of the shell, that when frightened 

 it retreated to the very uppermost whorl, and, notwithstanding the 

 wide mouth of the shell, could not be seen. So light was the weight 

 of the crab, that, on account of the buoyancy of its shell, it floated 

 lightl}' on the surface of the water, on which I had placed it with 

 the mouth of the shell uppermost, and was blown by a slight breeze 

 across a pool of water, some twenty yards in width. While it was 

 afloat, the shrewd little occupant retired to the innermost recess of 

 its home; but as soon as the shell had grounded, it protruded i's 

 head and ])incers and ^deavoured to overturn the shell, Avhich it 

 finally succeeded in accomplishing. 



In the case of these two genera of hermit-crabs, Coenobita and 

 Pagurus, it was intei'esting to notice the relation existing between 

 the defensive capabilities of the crab, and the relative size of the 

 shell it selected as its home. The Pagurus, with its weak slender 



