80 BY THE DEEP SEA. 



sometimes have brought in shore by a fisherman who has 

 discovered your weakness for what he will term " curios." This 

 is the Parasite Anemone (CHbrina fffoetd], which will almost 

 always be found perched on a full-sized shell of the common 

 whelk (Bucdnum undatuiii), or the red-whelk (Fnsus antiquus). 

 Yet the whelk-shell will not be tenanted by the whelk, but 

 by the Hermit-crab (Eupagurits bernhardus}. The Parasite, 

 when fully expanded, is about four inches high, and the 

 measurement across the tentacles is not much less. Its 

 column is pale drab in colour, the tentacles creamy white, 

 and the disk somewhat conical. To see a weak creature like 

 the Hermit hauling a heavy-looking shell along is a trifle 

 amusing ; but when Cribrina's huge tower of apparently solid 

 flesh is perched on top of that, the picture is absurd. Owing 

 to its large size and its unhappiness when deprived of the 

 society of the Hermit, the Parasite is not a desirable aquarium 

 specimen, except where one has very large tanks affording 

 sufficient depth and range for the Hermit-crab. It is not 

 clear what advantage each of the parties to this strange co- 

 operation gain, though it is easy to propound theories to 

 account for it. 



Such partnerships (commensalism] are by no means uncom- 

 mon in Nature ; and there is one subsisting on our own coasts 

 between another species of Hermit-crab {Eupagurus pride&Ux) 

 and the Cloaklet-anemone (Adamsia palliatd). It is probable 

 that the Anemone derives advantage from being carried about 

 from place to place, and thus has better opportunity for secur- 

 ing food than if stationary ; whilst the crab is probably saved 

 from being swallowed by a big-mouthed fish, owing to the 

 unpleasant odour of the Anemone. One other way in which 

 the Hermit may benefit is by feeding on the crumbs that fall 

 from the Parasite's table. I have had specimens brought to 

 me that had been hauled up on " spiller lines," the fishermen 

 characterising the Anemone as an enemy for stealing his 

 bait. Here probably the advantage gained by being perched 



