6584 Radiata. 



Carefully taking up the shell with the aquarium tongs, and bringing 

 it close to the surface, but not out of water, I gently dislodged the 

 Adamsia with my fingers, and allowed it to fall prone to the bottom. 

 I then released the shell and its tenant, and drove the latter towards 

 the spot where the zoophyte lay. 



No sooner did the crab touch the Adamsia than he took hold of it 

 with his claws, first with one, then with both, and I saw in an instant 

 what he was going to do. In the most orderly and expert manner he 

 proceeded to apply the Adamsia to the shell. He found it lying base 

 upward, and therefore the first thing was to turn it quite round. With 

 the alternate grasps of the two pincers, nipping up the flesh of the 

 Adamsia rudely enough, as it seemed, he got hold of it so that he 

 could press the base against the proper part of the shell, — the inner 

 lip. Then he remained quite still, holding it firmly appressed, for 

 about ten minutes ; at the end of which time he cautiously drew away 

 first one claw, and then the other ; and, beginning to walk away, I 

 had the pleasure to see that the Adamsia was once more fairly adhering, 

 and now in the right place. 



May 4. The Adamsia is again lost. On searching I discovered it 

 lying in a crevice, whence I plucked it, and laid it on the bottom. 

 Here again the crab found it, and immediately went through the same 

 process as last described, and again made it adhere. But I fear that 

 the Adamsia is unhealthy, for it seems to have but an enfeebled power 

 of retaining its hold. The manifestation of the mode in which the 

 instinctive actings of the two creatures occur, is, however, I think 

 sufficiently clear. The crab is certainly the more active promoter of 

 the partnership : it is abundantly evident that he values the company 

 of his elegant but very heterogeneous associate. These last observa- 

 tions have suggested a suspicion that the claws of the crab may have 

 been employed in the transference of the cloaklet from shell to 

 shell. 



The subject is one which will abundantly repay further investigation ; 

 and 1 commend it to the notice of those zoologists who have access to 

 the west coast of Scotland, where these animals appear to be most 

 common. 



P. H. Gosse. 



Torquay. 



