134 THE VICTORIAN NATURALIST. 



which constantly fall on the outer parts of the reef, breaking off 

 large masses of coral and heaping them on to the top of the living 

 coral, to which they become cemented, and so the surface of the 

 reef is raised above high water level, and on it debris of all 

 descriptions accumulates, and, disintegrating, forms a suitable 

 soil for the germination of seeds of plants and trees carried there 

 by the waves, wind, or birds, and thus plant and other life finds a 

 home. 



Owing to its isolation, many birds, particularly the Sooty 

 Terns, Sterna fuliginosa, repair to the Barrier Reef to breed, and 

 on approaching their " rookeries " thousands upon thousands of 

 birds can be seen sitting in compact masses on their nests. 



Frigate-birds, Fregata aquila, are also found frequenting the 

 same rookeries. These birds have been utilized by the traders 

 and missionaries of the South Sea Islands as letter carriers. 

 Captured when young they have an attachment for the home in 

 which they were reared, and, if taken away to another island, 

 will, when liberated, invariably return to their home. Taking 

 advantage of this fact, the missionaries forward birds by the 

 trading schooners to such places as they may desire communications 

 from, and, when the necessity arises, such as a hostile visit from 

 the natives, or pressing business communications, a letter is tied 

 to the leg of a Frigate-bird and it is released from its place of 

 captivity. Being strong fliers — in fact, the swiftest and most 

 powerful of all the ocean-roaming birds — they soon reach their 

 home, and alight on the perch where they had been fed during 

 their infancy. So powerful are these birds that they have been 

 observed to fly against the strongest cyclones that sweep across 

 the ocean. 



Crabs frequent the reef in large numbers, and act as scavengers, 

 but they can be a trouble to the naturalist, as on one occasion, 

 when camped on the reef, some valuable specimens which I had 

 left exposed were entirely destroyed by these voracious creatures. 



Many different kinds of coral are found on the reef, and may 

 in future years prove a valuable asset to the Commonwealth, as 

 from its calcareous nature it is a useful manure for exhausted 

 soils. It can also be used for the preparation of lime for build- 

 ing purposes, and, as the reef is, as I mentioned, some 1,300 

 miles long, the supply is practically inexhaustible. One must 

 not suppose that the coral reef resembles the bleached specimens 

 usually seen. When alive — that is, when tenanted by the polyps 

 by which it is formed — it assumes the most varied colours, and 

 to watch the animals in some calm pool expanding and retracting 

 their tentacles in search of food is indeed a fascinating sight. 



Holothurians, generally known as Beche-de-mer or Trepang, 

 abound everywhere along the reef. They are greatly prized by 

 the Chinese as an article of food, being considered a great 



