Pearls and the Pearl Fisheries. 



411 



years old ; from the fifth to the sixth year, however, the 

 pearl oyster doubles in value, and again doubles should 

 it survive to the seventh year. If removed too soon the 

 pearls are imperfectly formed, and, on the other hand, if 

 allowed to remain too long, the fish dies and is lost. 



The Ceylon pearl fishery usually lasts for a month or 



Fig. 29. 



I, Mehagrina margaritifera, the mother-of-pearl shell. 

 henulea, the Chinese pearl mussel. 



2. Amdonla 



six weeks, commencing about the second week in March, 

 and is carried on to the middle or end of April, when the 

 sea is usually calm and the currents least perceptible. The 

 following is from an account of the fishery which I pub- 

 lished in my " Technologist," vol. ii. p. 546 : — " The boats 

 employed are divided into two squadrons, each consisting 



