105 



(p. 38), as being a distinguishing characteristic of this bank 

 as compared with the Tholayiram Par, are very abundant, 

 and belong to the genera Madrepora, Movtipora, Sydnopliora^ 

 Porites, Pocillopora, Galaxea, C//phastrcea, C(sloria, Favia, and 

 Goniastrcea ; the living corals growing on the shells of living 

 oysters, which, did they migrate, would have, sometimes, 

 to carry about with them a weight of nearly 8 ounces. 

 The coral-incrusted shells had, prior to the fishery of the 

 Muttuwartu Par this year, only been seen by Captain 

 Donnan on the North-west Cheval Par; and, when the 

 oysters disappeared from the latter in 1888, the drift-oysters, 

 which were eventually found, were recognised by the 

 coral-growths upon them. Arborescent sea-weeds, forming 

 tangled masses, such as abound on the Tholayiram Par, were 

 conspicuously absent ; but the oyster shells were largely 

 encrusted with incrusting sponges, and the orange- coloured 

 Axinella donnani, which receives its specific name after the 

 present Inspector of Pearl Banks, was very common. In 

 addition to the shell-incrusting corals massive corals, mainly 

 belonging to the genus Madrepora, flourish on the bank, 

 forming a convenient habitat and hiding place for Annelids, 

 Crustaceans, Molluscs, &c., which can live there safe from the 

 attacks of predaceous enemies. The sea bottom is, so far as 

 I could gather from repeated examination, on different parts 

 of the bank, of the residue left after shaking up the oysters 

 in a bucket of water, and of the contents of the digestive tract 

 of a Holothurian {H, atra) which abounds on the bank, 

 mainly composed of a white deposit, such as I have only seen 

 on the Indian Coast of the Grulf of Manaar, which is composed 

 of a calcareous Alya and Foraminifera, among which Rotalia 

 calcar^ Heterosteyina depressa, and Amphistegina lessonii are 

 the most conspicuous. It was long ago pointed out by 

 Captain Steuart that the places, on which pearl fisheries 

 have been successfully held in Ceylon, appear to be beds of 

 Madrepore of irregular heights, having the spaces between the 

 ridges nearly filled up with sand. The transparent clearness 

 of the water over the banks, and the clean state of the sea 

 bottom, which is free from sediment carried down by currents, 

 must, I think, be regarded as important conditions favouring 

 the healthy growth of the oysters thereon. 



Swimming about on the surface of the water over the 

 bank were many black and yellow striped sea-snakes, which 

 are believed by the divers to feed on the oysters. Indeed, 

 in 1862, the Eui'opean diver reported that he had seen the 



