CRUSTACEA OF THE LAND 199 



with their claws, and in doing so actually punched 

 holes quite through the tin. 



The breeding habits and mode of development of 

 the Robber Crab have often formed the subject of 

 inquiry by naturalists, but it is only recently that 

 Dr. Willey has been able to prove definitely that the 

 female visits the sea for the purpose of hatching off 

 the eggs, and that the young are hatched in the zoe'a 

 stage. The larvae obtained by Dr. Willey have been 

 described by Mr. Borradaile, who finds that, as was 

 to be expected, they closely resemble those of 

 Ccenobita. There appears, however, to be no such 

 simultaneous migration of the Crabs towards the sea 

 as has been described in the case of the Gecarcinidae. 

 The statement, quoted by Darwin, that Birgus visits 

 the sea every night for the purpose of moistening its 

 branchiae, cannot be universally applicable, since the 

 Crabs are often found, as on Christmas Island, at 

 distances from the sea which put a nightly journey 

 to it out of the question. 



Of all Crustacea, the most completely adapted to 

 terrestrial life are the Land Isopods, or Woodlice, 

 which may be found in every garden. It is true 

 that most species are found in damp places, although 

 some that inhabit the sandy deserts of Asia and 

 Africa must be content with a very slight degree of 

 humidity ; and in no case is their dependence on 

 moisture greater than, for instance, that of many 

 Insects and Arachnids which are regarded as typically 



