114 



CEYLON PEARL OYSTER REPORT. 



" rock." There are few attached coral colonies, but very many of a thin brown species 

 of Flabellum lying on the sand. 



This paar presents an excellent bottom both for the deposit of spat and also for 

 dredging. 



MlJTTUVARATU PaAR (DoNNAN's). 



This lies 5 miles west of Karativo Island and 3 to 4 miles south of Hamilton's 

 Alantura Paar. It is 2j miles long (north to south) and 1^ miles wide (east to west). 

 The depth is 5 to 10, mostly 7 to 8 fathoms. On the whole it has a level hard 

 bottom, and any little sand present is Foraminiferal. Of 289 dives, all were upon 

 " rock," and 238 yielded adult oysters. Only the dives to the west part, in deeper 

 water (fig. 39, A), were unproductive. This paar was covered, when we examined it, 

 with plenty of pearl oysters, which are small for their presumed age, but thick, and 

 with little or no signs of rapid or recent growth on the margins. 



Oysters on this paar are rather characteristically associated with corals of the 

 genera Madrepora, Porites, Pocillop07-a, Montipora, Favia and Goniastrea, growing 

 upon the left valves which always lie uppermost in the usual position of the oyster 

 (fig. 38). Some specimens are much overgrown with Polyzoa, sponges, &c. The 



Fig. 38. Old pearl-oysters from the Muttuvaratu Paar, with large Madrepore Corals growing on the 



shell half natural size. 



oysters are also notably stunted in appearance, and their small size, compared with 

 oysters of the same age from Cheval Paar, is well known, and has been recognised by 

 various writers. 



We found the specific gravity of the sea to be unusually low in this neighbourhood 

 (r0208, at a temperature of 85 F.). This may be due to proximity to the mouth 

 of Putlam Lake, which probably discharges a considerable amount of fresh water 

 derived from the Kala Oya and the Mi Oya "Rivers. The bottom on this paar is flat 

 " rock " with many small colonies of Astrcea, Cceloria, and allied low-growing 

 corals, with occasional bushes of large branched Madrepores, such as M. cervicomis 

 and M. cytherea, rising to 18 inches or 2 feet in height. The pearl oysters on this 



