HOUTMAN'S ABROLHOS. 139 



laid down, the sea-bottom was covered by coral banks of considerable extent, 

 which were composed exclusively of representatives of the genus Turbinaria. Turbinaria 

 conspicua, a most luxuriant foliaceous species, and irregular dome-shaped masses of 

 T. peltata, represented the dominant forms upon these banks. Specimens of these 

 Madrepores, no less than five feet in diameter and some fifteen feet in circumference, 

 were secured by the author from this locality and are now on exhibition in the Coral 

 Galleries at the Natural History Museum, South Kensington. They constitute, up to 

 the present date, the largest examples of Madreporidce yet brought to England, or, 

 indeed, to any European museum. 



It is worthy of record in this connection that the genus Turbinaria has, as the 

 result of a somewhat extensive investigation of the coral reefs around the Australian 

 coast, been found by the author to enter most extensively into reef-composition in the 

 colder, or extra-tropical, areas within Australian waters. They have, in this 

 manner, been observed by the writer to predominate in the reefs in Wide Bay, 

 Queensland, on the southern outskirts of the Great Barrier Reef; in the colder, 

 though more northern, inter-tropical waters of . the Gulf of Carpentaria ; and, 

 finally, in the Shark's Bay district of Western Australia. It should be further men- 

 tioned that these Turbinaria reefs, while attaining to within a short distance of the 

 surface of the water, are never exposed above it by the falling tide, as commonly 

 happens in reefs of mixed Madreporidce growing within the tropics. A fuller reference 

 to these Shark's Bay Turbinaria, together with illustrations of the more prominent 

 species, will be found in that portion of Chapter VIII. which specially deals with 

 Corals and Sea Anemones. 



The most prominent testimony indicating that the Houtman's Abrolhos 

 reefs were better suited even than Shark's Bay for the introduction and cultivation of 

 the large tropical Pearl Shell, was afforded by the composition of the reefs. These, 

 in place of being built up of the extra-tropical or cold water Turbinarue that flourish 

 in Shark's Bay, were composed of numerous varieties of branching Madreporce, or 

 so-called Stag's Horn Corals, with which were intermingled many species of Porites, 

 Montipora, Pocillopora, Seriatopora, Cceloria, Goniastrcea, Mussa, Symphyllia and other 

 essentially tropical generic types. Typical examples of all these genera are, in fact, 

 included in the collection from these reefs presented by the writer to the British 

 Museum. 



The reef corals of Houtman's Abrolhos, while growing very near to the surface 

 level of the water at low ebb tide, very rarely appear above it, and then to the extent 



