eupagtjeus. 555 



Its Habitation. 



The possession of a shell of foreign origin has 

 probably had more share in attracting the attention of 

 naturalists to the hermit crab than any other of its 

 habits. The tenant's right of ownership was the chief 

 problem. Swammerdam went so far as to argne that 

 the shell was actually secreted by the inmate, and 

 supported his contention by various ingenious arguments. 

 Later observers took the less charitable but, unfortunately 

 for the animal's reputation, the more tenable view that 

 the shell had been obtained from a friendly or perhaps 

 a much wronged Gastropod Mollusc. Whether the crab 

 had simply appropriated the vacant home of a deceased 

 whelk, or whether it had forcibly ejected the owner of 

 the shell — added "murder to piracy" — was the question 

 to be decided. 



Bell argued from the fresh and clean shells in which 

 hermits are frequently lodged that they attack the living 

 niollusc and eat it out of its home. In fact, he 

 considered that they are designed to keep the mollusc 

 population in check. This idea seems to be strengthened 

 by the fact that fishermen sometimes trawl the animals 

 in the act of eating the whelk from its shell, presumably 

 in anticipation of using it for a covering. Bell's 

 argument and the fishermen's observation are quite 

 accurate, but they do not prove that the hermit crab 

 attacks the living Gastropod. In the first place it is 

 not very conceivable that a hermit crab would have the 

 strength to remove bodily, or the appetite to devour, an 

 extremely tough animal like the whelk. Such an 

 objection, however, does nothing to elucidate the facts 

 which have been stated, but I think the following 

 suggestion will go a long way towards meeting them. 



