CHAPTEK XV 



THE STRUCTUEE OF THE ISLANDS 



In describing the general structure of the atoll it was noted 

 that not only did the whole system of islands tend to be 

 circular, but that the general plan of the atoll — the " fairy 

 ring " — was foreshadowed in the structure of every constituent 

 island ; and a glance at the chart will show this fact. The 

 most common form of the islands is the crescent, and this is 

 only to be expected, as many of them are considerable portions 

 of the circumference of the atoll ring : but this feature goes 

 still further, and in many cases the extended horns are bent 

 inwards until the island itself becomes an incomplete circle, 

 and itself rises to the dignity of enclosing a lagoonlet. Pulu 

 Panjang encloses two such lagoons, and Pulu Atas three ; 

 whilst Pulu Ampang major and Pulu Pandan are advanced 

 approximations to the circular form. 



These lagoonlets are places of great interest, for they have 

 to some extent a flora and fauna of their own ; they also show 

 the final stage of coral degradation, for they are composed of 

 a Avhite, chalky — almost slimy— ooze, which is dry at low 

 tides, and partly dry for the greater part of the whole tide 

 cycle. The degradation of the coral sand that has taken place 

 in the lagoonlets is doubtless partly a sub-aerial decomposition, 

 and partly the life-work of the many creatures that live in 

 these oozy flats. The " fiddler crabs " (Gclasimus, sp.) with 

 one great pink claw, larger than all the rest of the crabs, live 

 in myriads in little holes in the white mud ; and when 

 disturbed they beat a steady line of retreat, marked by the 

 rolling onwards of a pink wave, which fades away before you, as 

 each one seeks refuge in his burrow. The large Kapeting 

 Balong (Gardiosoma, sp.) lives round the margin of the 



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