28 



on to, or keeping near tlie bamboo, broke off as large a mass of 

 oysters as he could conveniently bring to the surface in one 

 liand, and with the other he helped himself up the bamboo. 

 Any mussels that were found adhering to the block of oysters 

 were secured, and the oysters were returned to the water, as 

 thousands of them have already, from time to time, been ex- 

 amined in vain. I was amazed at the dexterity and rapidity 

 with which the divers opened the mussels with knives made for 

 the piu'pose ; and the expert manner in which they ran their 

 thumbs over the molluscs, detecting in an instant without fail 

 the most minute seed pearl not larger than a pin's head, leaves 

 no room for doubting that long practice has made them perfect 

 in this particular branch of what has hitherto been to them a 

 highly lucrative employment." 



The flat, transparent shells of F lacuna placenta (window 

 shell) are used in China and at the Indo-Portnguese Settle- 

 ment G-oa as a substitute for window glass ; and the small 

 pearls which the animal produces are exported to India to 

 be calcined into chunam, which rich natives chew with their 

 well-beloved betel, and are said to be burned in the mouths 

 of the dead.^ So far as I am aware the pearls which might 

 be obtained from the masses of P lacuna which live in the 

 mud flats of Southern India have not been utilised as an 

 article of commerce. But an extensive Placuna pearl fishery 

 has been carried on at Tamblegam lake in Ceylon ; and some 

 idea of the abundance of the mollusc may be gathered from 

 the fact that the quantity of shells taken in the three years 

 prior to 1858 could not have been less than eighteen millions. 



1 Vtde Tennent's Ceylon, II, 492. 



