THE PEARL OYSTER. 937 



sizes, with the view of separating the larger, and of thus 

 fixing a standard of size and worth. There are generally 

 twelve sieves, set one within the other, and each is pierced 

 with a certain number of holes, varying from 20 to 1000. 

 The pearls which do not pass through any sieve containing 

 above eighty holes are of the larger size, and are named 

 first-class, or mill pearls. Those which lie between the 

 sieves containing from 100 to 800 holes, are known as 

 vivadce pearls, or those of the second class. Those which 

 pass through the remaining sieves, and at length reach the 

 1000 holed sieve, are the seed or dust pearls, and are of 

 comparatively small value, being sold by weight or mea- 

 sure, to be converted into powder. The larger pearls are 

 threaded, and are exposed for sale in rows. The American 

 pearl-oysters are opened by knives, and the pearls are 

 sought for at once among the fresh tissues of the animal 

 a process which, though less certain of securing the con- 

 cretions, is yet said to have the merit of obtaining them in 

 a fresher state, and less liable to discolouration. 



The Indian pearl-fisheries of the Bay of Bengal, those 

 of Japan, of China, and of the Eastern Archipelago, are 

 estimated to yield an annual produce of about ^"800,000. 

 The fisheries of the Isle of Bahrein, on the coast of Arabia, 

 in the Persian Gulf, produce about ^"240,000 annually ; 

 all the Arabian fisheries yielding an annual total of about 

 .350,000. The South American pearl-fisheries of the 

 Mexican coasts, and of the Islands of Panama, Margarita, 

 &c., were formerly in high repute. In the time of Charles 

 V. of Spain these fisheries sent pearls to that country of 

 the value of ,160,000. The present value of the South 

 American fisheries is stated as averaging about ,60,000 

 annually. 



