MOLLUSCA. 187 



net or basket. Every diver is armed with a powerful 

 knife, by means of which he detaches the Avicula 

 from the rocks, and which serves to defend him in 

 case he is attacked by a shark. There are marvel- 

 lous stories told of the length of time these divers 

 can remain under water ; but persons who have 

 inhabited Ceylon for many years assure us that 

 they never saw a diver remain submerged for more 

 than fifty seconds at a time. They plunge and 

 relieve each other by turns, from daybreak till 

 about ten in the forenoon, when the sea-breeze sets 

 in, and the whole flotilla return to shore. In a short 

 time we shall probably see those iron head-cases 

 and tubes, now used by the divers at work in the 

 Thames, adopted by those of Ceylon. The pearl 

 oysters are taken from the boats, and heaped upon 

 the shore to putrefy. For this purpose an enclosed 

 space of ground is allotted to them. As soon 

 as the putrefaction is sufficiently advanced, the 

 shells are taken and placed in troughs, where sea- 

 water is thrown upon them. When decomposition 

 sets in, the body of the mollusc soon ceases to 

 adhere to the shells and the pearls they contain, 

 which are then taken out, washed, and assorted. 

 The pearl fishery of Ceylon, in 1857, brought in 

 20,550 15s. 6d.; the same year chank-shells, before 

 mentioned, realized 188 95. 



Such is the present state of things. Our readers 



