L02 CEYLON PEARL OYSTER REPORT, 



57 '54 x 54 "00 X 24 -42 millims., all being of the same season, from 3J to 3f years old. 

 The stunting, although less marked than in the case of the Muttuvaratu Paar, is 

 apparently a permanent characteristic of the North-west Cheval, and is flue, we 

 consider, to the conditions which favour an abundant deposit of spat leading afterwards 

 to overcrowding and insufficient food. 



The characteristic organisms on the bottom are : 



Saiyassiini and other Algae (Padina and small Floridese) in profusion ; 



Spongionella nigra, and a few Corals such as Turbinaria cinerascens and some 

 Astrasids ; the large red starfish Pentaceros lincki, a fine species of Cidaris and 

 Antedon. Quantities of Aplysia were seen, also LameJlaria, Chromodoris, Scyllcea 

 and Eolids ; Pinna lay flat on the rock in place of being partially buried in sand. 

 The large pinkish Ascidian Rhabdocynthia rosea was also present. 



East Cheval. The bottom here consists of fragments of rock embedded in or covered 

 with a few inches of sand. One piece brought up by the divers from the North-East 

 Cheval (6^ fathoms) was a tabular calcareous mass, 4 feet by 2 feet by 4 or 5 inches 

 thick, upon which about a dozen pearl oysters were attached, distributed as 

 follows : One end of the block projected above the sand and bore most of the 

 oysters and some small Alga?, &c. ; the other end was covered with a thin layer of 

 sand, but had 5 oysters attached, the byssus passing through the sand to join the 

 rock below several other byssus tufts were also present ; finally the middle, lowest, 

 part was more deeply buried in sand and showed no trace of oysters. This case was 

 typical of many '" rocks" examined. The block was composed mainly of dead coral, 

 upon which old worn shells and quartz grains had become cemented; partly by 

 deposition of carbonate of lime and partly by incrusting calcareous Algae, Polyzoa. 

 and Serpulid tubes. The deeper parts showed ferruginous staining, and the cavernous 

 condition of the interior in this and other blocks was due partly to the irregular 

 disposition of the original components now cemented, and partly to boring by Clione 

 and Molluscs. While at the north end of the paar the rock seems to be mainly dead 

 coral, a little further south it becomes a grey-green compact grit stone cemented by 

 carbonate of lime and incrusted with Nullipores and Polyzoa. 



Over much of the East Cheval sand predominates on the surface, underlaid by 

 rock, at a depth of 6 inches to 2 feet, from which in places corals and other colonies 

 project above the sand. The pearl oysters, in our experience, were fairly evenly 

 distributed, and in quality they proved to be the best of all those examined or fished. 

 They were well-grown and vigorous (fig. 29), and richer in good pearls than any 

 others. 



In the sandy parts the pearl oysters are attached through the sand to buried 

 fragments of rock, coral, or any firm substance. Sometimes one oyster is attached to 

 a piece the size of a walnut, and two or three others are fixed to the shell of the first. 



On this part of the paar large Algae are scarce, but there were plenty of small 

 Floridese, Padina, Laurencia (boiled into jelly and eaten by the natives), Poly- 



