THE LITTORAL AND MARINE FAUNA 319 



crab is a minute creature and is very similar to Mdia 



tessellata, described by Mr. Borradaile as living in the Male 



atoll and elsewhere. The crab is rather conspicuously marked, 



but it has adopted the curious habit of carrying a bouquet of 



green algse in its claws, and behind this bouquet it hides its 



boldly marked body. In 



the cases which I have Fig. 70. 



examined the alga had 



actually taken root upon 



the claw, for it had been 



held so long in position ; 



but there seems to be no 



doubt that in the first 



place the crab plucks 



the alga and carries it 



in front of its body as 



a kind of stalking-horse, 



and as a shelter from its Small Crab that holds in its Claws 



TWO SMALL Bouquets of Living Alg^e. 



(Enlarged to twice natural size.) 



enemies. 



It must not be for- 

 gotten that the creatures 



that live in the waters of the lagoon, no less than those that 

 have invaded the land, are properly a part of the peculiar 

 fauna of the group. For those animals which spend their 

 lives in the shallow waters of the coral beds there is no 

 feeding-ground nearer than the coast of Java, or the shores 

 of Christmas Island, five hundred miles away. The greater 

 part of all the fish about the atoll in all probability spend the 

 whole of their lives in its immediate vicinity, and the many 

 beautiful little coral-haunting species of the lagoon belong 

 peculiarly to the local fauna. 



The fish are necessarily among the most economically 

 important animals of all the fauna of coral atolls, for they 

 furnish an abundant supply of fresh food in these places in 

 which it is otherwise very scarce. It is fortunate that of all 

 the quaintly shaped and gaudily coloured atoll fish, there is 

 only one which is poisonous when used for food, and even that 



