318 JOURNAL, BOMB A? NATURAL HISTORY SOCIETY, Vol. XI. 



page 124 : " The young are hatclaeii within the body of the parent and are 

 discharged in cloud-like swarms of tiny creatures to seek each its own living. 

 The embryos at first swim freely about, in which stage they represent the 

 permanent condition of the Pteropoda, but soon dropping* their filamentous 

 organs, of motion, as tadpoles do their tails, they either attach themselves 

 permanently to any convenient roosting place within their reach, as Ostrea 

 or Chama, moor themselves securely by a byssus or cable, like Pinna or 

 Mytilus, or lead a free and roving life, like Cardium or Union.' 1 See also 

 Dictionary of Economic Products, vol. vi, page 121, where the following 

 passage occurs : " The molluscs possess locomotive powers and frequently 

 disappear from certain banks and migrate to more favourable situations." 

 The Burmans say that no bed is known to be in existence for "more than six 

 years. During that time the action of the sea either covers them up with 

 mud, thus smothering tharn, or breaks them away from their moorings, doing 

 them mortal injury. 



The numbers to be found, in one bed varies very much ; sometimes many 

 millions are found ; at others only a few thousands. Sand appears to be the 

 favourite bed, though mud is also appreciated. The oyster" is also to be 

 fou d on rocks, but not in such large numbers as on sand and on mud. This, 

 the Burmxns explained to me, is besuise there is only a limited supply of rocky 

 bottom, whereas the other two are practically unlimited in extent. I see 

 however, from the Agricultural Ledger, No. 36 of 1896, that the oyster prefer 

 a muddy bottom (see page 5). The pearl is said to appear when the oyster is 

 about three years old — that is to say, never before two years and never after 

 four years. The pearls are very minute and require a microscope to see them, 

 but a pair of sharp eyes can occasionally pick out the larger pearls. On en- 

 quiring why the pearls are so small, the villagers say that the pearl as it grows 

 prevents the oyster from closing and so allows the mud and saud to get into, 

 the shell and thus to kill the oyster. You will observe from the shells sent 

 that they are remarkably flat and that the smallest obstruction would prevent 

 the oyster from closing. In many oysters that I examined I found three, 

 four, and once as many as eight, small pearls, and I am informed that some- 

 times as many as fifteen are found, but they are so infinitesimally small that 

 it is extremely difficult to count them. When the larger pearls are found, 

 they are found usually singly. 



The Modus operandi of getting the pearls away from the flesh is as f ol- 

 lows:— The oysters having been collected are put into a large cauldron of 

 hot water ; they then open and keep open. The flesh is then scraped off the 

 shell with a knife and thrown into a basin. When the basin is half full, it is 

 put into the sun, and the flesh allowed to decompose. After three or four 

 days, when the flesh has more or less thoroughly decomposed, water is added 

 and the whole mess stirred. The pearls being heavier than the decom- 

 posing and decomposed oyster fall to the bottom and are easily got out of 



