318 CORAL AND ATOLLS 



■ — making an ever-increasing army, the nearer they get to 

 some piece of sea-tossed carrion, is something to watch on 

 tedious coral island days. Very often in the early morning 

 an army will be seen on the beaches, drawn up in a circle, all 

 beginning to turn homewards from the feast upon the body of 

 some fish that has been cast ashore, for a dead shark will 

 collect around it half the hermit crab population of the island. 

 None of these crabs is used for food except the Kapeting 

 lalong and the Birgus, and at the present time so few of this 

 latter species are to be found that its dietetic importance has 

 ceased. The hermit crabs are, however, extensively used for 

 bait, and the big Kapeting halong, put whole upon the hook, 

 makes the best and most attractive bait for the green-fish. 



One crab, named Kaijcting trcleh, a member of the genus 

 Ze^ytograpsus, is very good eating indeed, and, as it is an 

 abundant species upon the seaward side of the islands, it is to 

 be ranked among the useful animals of the atoll. 



In the calm waters of the lagoon, and in the rock pools of 

 the barrier, are a myriad forms of crabs, strange and grotesque 

 in shape and often of very beautiful colours, each marvellously 

 fitted to the environment in which it finds itself. In every 

 colony of coral is some tiny crab, always adapted most wonder- 

 fully to its place of residence, and often it is almost impossible 

 to distinguish these coral crabs from the branches of the type 

 of coral upon which they dwell. Many of them bore holes in 

 the coral rock, and these are very difficult to see, for they are 

 small and coloured like the surface of the rock which they 

 inhabit, and one is generally not aware of their presence until 

 they have withdrawn into their holes. Some that live in the 

 soft lagoon sand, as Calapjpa hepatica, are strangely like a 

 fragment of coral conglomerate, for, as they lie in the ooze, 

 their legs are pressed firmly against their shell and not a 

 joint in their whole body is to be seen. 



The whole crab fauna of the lagoon and barrier is too 

 numerous to discuss in detail, and the names of only a very 

 few of the army are recorded in the appendix to this chapter ; 

 but one rock-pool crab deserves an especial notice. This 



