( 49 ) 



Ostreci, is that the pearl oyster, like our common mussels, has a 

 'byssus' or bundle of tough threads by which it can attach itself 

 to rocks or other foreign objects." * 



The collection shows pearl oysters from sevei-al paars in various 

 stages of growth, and other organisms, corals, pennatulids, sponges, 

 sea urchins, &c., which also grow on the pearl banks in association 

 with the pearl oysters. Of special interest are the specimens 

 prepared in spirits showing pearls in situ. 



Large specimens of stone corals (Madreporaria), sea shrubs 

 (Gorgonacea), black corals (Antipatharia), and leathery corals 

 (A-lcyonacea) from Galle and the Maldive Islands are exhibited 

 in wall cases in the fish alcove and on the south verandah. Those 

 from the Maldive Islands were presented by Mr. J. Stanley 

 Gardiner, M.A., who organized an expedition for the investigation 

 of the coral atolls of the Maldives in the years 1899-1900.t 



The dried corals which are exhibited are the basal and axial 

 skeletons secreted by the soft parts of the living coral polyps. 

 These form large colonies by a peculiar process of budding and 

 branching, and deposit the mineral substances which they have 

 absorbed from the sea water so as to form the wonderful growths 

 which remain after the living tissues have been removed. 



The Madreporaria are the reef-building corals forming extensive 

 reefs at Galle and oflE Jaffna, and especially at the Maldive Islands, 

 which are themselves partially elevated coral reefs. The pearl 

 banks are not coral reefs, but sandbanks, formed of sandstone 

 and concretions upon which isolated corals grow without forming 

 reefs. 



* Cf. Report to the G-ovemment of Ceylon on the Pearl Oyster Fisheries of the 

 Gulf of Mannar, by W, A. Herdman, D.Sc. F.R.S., with supplementary reports 

 upon the Marine Biology of Ceylon by other naturalists. Published by the Royal 

 Society, Part I., Lqudon, 1903. Professor Herdman and Mr. Hornell arrived in 

 Ceylon in January, 1902, and the former left in the following April. Since then 

 the work has been carried on locally by Mr. Hornell. 



§ The Fauna and Geography of the Maldive and Laccadive Archipelagoes. 

 Edited by J. Stanely Gardiner. Vols. I. and II., 1901-1905 (Cambridge University 

 Press). 



H 105-04 



