CRUSTACEA OF THE LAND 195 



The author just quoted describes a visit to Pitti 

 Bank in the Laccadive Archipelago, the breeding- 

 ground of two species of terns. The ground was 

 everywhere strewn with the dead bodies and clean- 

 picked skeletons of the young birds. " We soon dis- 

 covered that one great cause of the wholesale 

 destruction of young birds was the voracity of 

 swarms of large Hermit Crabs {Ccenobita), for again 

 and again we found recently killed birds, in all the 

 beauty of their first speckled plumage, being torn to 

 pieces by a writhing pack of these ghastly Crus- 

 taceans. There were plenty of large Ocypode Crabs, 

 too (0. ceratophthalmus)f aiding in the carnage." 



On Christmas Island Dr, Andrews found a species 

 of Ccenobita not unfrequently in the higher parts of 

 the island far from the sea, and he remarks that the 

 occurrence of large marine shells high up on the 

 hills seemed very puzzling until it was noticed that 

 they were brought by the Hermit Crabs. 



The species of Ccenobita possess a very curious 

 adaptation for aerial respiration. The soft skin of 

 the abdomen is traversed by a network of blood- 

 vessels and acts as a kind of lung, and a pair of 

 contractile vesicles at the base of the abdomen serve 

 as accessory hearts in promoting a specially active 

 circulation in that part of the body. The lining 

 membrane of the gill chambers also appears to aid in 

 respiration as in other terrestrial Decapods. 



The " Robber Crab " or ** Coconut Crab " {Birgus 



