380 



SHELLS. 



[Chap. XL 



the inspection served only to suggest the prospect (which 

 has since been realised) that in time the income from 

 this source might be expected to revive; — and, forced 

 to content ourselves with this anticipation, we weighed 

 anchor from Condatchy, on the 30th March, and arrived 

 on the following day at Colombo. 



The banks of Aripo are not the only localities, nor is 

 the avicula the only mollusc, by which pearls are fur- 

 nished. The Bay of Tamblegam, connected with the 

 magnificent harbour of Trincomalie, is the seat of 

 another pearl fishery, and the shell which produces them 

 is the thin transparent oyster (Placuna placenta), whose 

 clear white shells are used, in China and elsewhere, as 

 a substitute for window glass. They are also collected 

 annually for the sake of the diminutive pearls contained 

 in them. These are exported to the coast of India, to 

 be calcined for lime, which the luxurious affect to chew 

 with their betel. These pearls are also burned in the 

 mouths of the dead. So prolific are the mollusca of the 

 Placuna, that the quantity of shells taken by the 

 licensed renter in the three years prior to 1858, could 

 not have been less than eighteen millions. 1 They de- 

 light in brackish water, and on more than one recent 

 occasion, an excess of either salt water or fresh has 

 proved fatal to great numbers of them. 



On the occasion of a visit which I made to Batticaloa, 

 in September, 1848, I made some inquiries relative to a 

 story which had reached me of musical sounds, said to be 



given from drawings made for the at four months old, No. 3. No. 4, 



Official Inspector, and exhibiting six months. No. 5, one year. No. 



the ascertained size of the pearl 6, two years. The second plate 



oyster at every period of its growth, exhibits the shell at its full growth, 

 from the "spat" to the mature 1 Report of Dr. Kelaart, Oct. 



shell. The young "brood" are 1857. 

 shown at Nos. 1 and 2. The shell 



