208 IN AUSTRALIAN WILDS 



scarlet, silver, gold, orange-brown, and green be- 

 ing among the colours displayed by different species. 

 Tiny fishes, which haunted the branches of living 

 corals, harmonised with their surroundings, and were 

 detected only when frightened away from their 

 shelter. It was the same with crustaceans and other 

 animals. 



The reef at low tide was exposed for some four 

 miles from east to west, and less than half that dis- 

 tance from north to south. It proved to be a rich collect- 

 ing place. Overturning "nigger-heads," we found num- 

 bers of molluscs, sponges, echinoderms, and so forth. 

 Cowries were so abundant that one could gather a 

 bucketful in an hour. Some were large, but a small 

 species, with a delicate violet-coloured shell, was most 

 attractive. As a rule, the shell was concealed by a black 

 mantle. It was necessary to shatter clumps of coral 

 in order to obtain some of the cowries, which were 

 buried among the branches. Tridacna shells of 

 large size were numerous, the finest specimens being 

 in the lagoon. A few "nigger-heads" were collected 

 on the crest of the reef and carried ashore, but they 

 were too bulky to pack in specimen cases, and were 

 abandoned when we left the islet. These curious 

 objects are composed of an Astrean species of coral; 

 they are roughly globular, and of a dark colour. At 

 Mast Head many of the "nigger-heads" were tufted 

 with purple-shelled rock oysters. 



We waded in the lagoon at low tide, when the 

 dead tops of coral masses showed above the surface. 

 The "floor" of the lagoon was nearly covered with 

 living coral. Sandy channels intersected the sub- 

 merged "tableland" composed of clumps of Madre- 

 pora, Turbinaria, and other corals which sometimes 

 crumbled as we walked along it, with the result that 

 our legs were scratched by the jagged fragments. 

 The colours of the corals included purple, violet, 

 yellow, brown, green and crimson, and we never tired 



