PLACUNA FISHERY. 135 



Date. Observations. 



June, 1907 .. Average of 12: 150-5 by 142-5 mm. 



The difference in average long diameter 

 between this and the 1905 sample is 

 negligible and the height is the same. 

 I assmne that they belonged to the 

 same generation, and were therefore 

 more than 4 years old. 



October, 1907 . . Average of 20 : 154 by 149 mm. 



March, 1908 Average of 20: 166*4 by 1.54-75 mm. 



Shells very old, heavy, and mostly worn 

 at the edges ; some blackened (" mica- 

 ceous ") about the hinge ar«a. 



Table V . — Polokarai-aru. 



This bed lies rather near the shore, between Sembian-aar and 

 Kakkaimunai. 



October, 1907 . . Oysters scattered like those of Sembian- 



aar. Average of 18: 154-7 by 149-6 

 mm. 



Table VI. — Uppu-aru. 



I inspected this bed in March, 1908, with an entirely negative 

 result, apparently due to an excessive deposition of mud during the 

 recent rains. This backwater is a simple estuary, whereas the 

 Tarableganl lake is to a great extent an arm of the sea. 



III.— The Fishery of 1908. 



The measurements tabulated above show that the oysters living 

 in the lake at the time of the 1908 fishery were to all intents and 

 purposes of the same age. There was not one too young to be 

 taken by the divers, no fall of spat being known since 1904-1905. 

 It follows from the facts wliich have been brought forward that the 

 fishery of this year has not been an independent fishery like the 

 annual Mannar fisheries, but it has been the conclusion of the 

 industrial collection of one growth, or, to use an agricultural 

 expression, one crop of Placuna. 



The fishery commenced on February 3 and ended on March 17. 

 Although short it went briskly, being better organized than in the 

 previous year ; and it gave better results in consequence of this fact, 

 and also because of the increased average size of the pearls. 



Arrangements had been made for the filling in of forms of daily 

 return signed by the manager of the fishery on behalf of the lessees. 

 These offered no difficulty of any kind and yielded just the infor- 

 mation that was wanted and would otherwise have been lacking. 

 Their use should be made an indispensable condition of future 

 fisheries. 



The total number of oysters recorded as having been taken in 

 1907 was 1,255,344. Of these, one-half belonged to the lessees, the 

 other half to the divers ; and the half share of pearls secured by 

 the former amounted to the weight of 46 rupees, valued by weight 



