CRUSTACEA OF THE LAND 197 



traversed by numerous bloodvessels ; but in this case 

 its efficiency as a lung is added to by numerous 

 tufted papillae, which increase the surface exposed 

 to the air. 



As in other Hermit Crabs, the last two pairs of 

 legs are shorter than the others, and they end in 

 small chelae. The last pair are very slender, and are 

 usually carried folded up within the gill chambers, 

 which they possibly serve to keep clear from foreign 

 bodies. The penultimate pair of legs are stouter, 

 and the two pairs in front of these are long walking 

 legs. The chelipeds are very strong and are of un- 

 equal size. When attacked, the animal defends 

 itself, not, as might have been expected, with its 

 chelipeds, but with the first pair of walking legs, the 

 sharp points of which form very efficient weapons. 



The statement that the Robber Crab climbs lofty 

 trees was first made by the Dutch naturalist 

 Rumphius, in the beginning of the eighteenth 

 century. Its accuracy has been often doubted or 

 denied since then, and only finally put beyond 

 dispute by a photograph taken on Christmas Island 

 by Dr. Andrews, which shows one of these Crabs in 

 the act of descending the trunk of a sago-palm. It 

 seems not impossible that the habits of the animal 

 may vary to some extent in different localities, and 

 that where food is abundant on the ground the tree- 

 climbing habit may be in abeyance. If this were so, 

 it would explain the very definite statements made 



