76 Pearls. 



exceeding in size the palm of a man's hand, and 

 though it exhibits the most brilliant nacre, and pro- 

 duces fine small Pearls, its shell has but little market 

 value as mother-of-pearl, being worth only from 

 20S, to 30J. per ton. On the other hand, the Me- 

 leagrina margaritifera is considerably larger and 

 thicker, and yields the most valuable mother-of- 

 pearl, as well as the finest Pearls, although these 

 are not numerous. Indeed so pronounced are the 

 differences between the two species in this respect, 

 that the former might, with propriety, be called the 

 ** Pearl," and the latter the "Shell" oyster. 



The number of Pearl-producing molluscs, how- 

 ever, is by no means confined to the Aviculidce: 

 they are on the contrary members of a very large 

 group, which frequently differ from each other in 

 almost every other possible respect : indeed their 

 general configuration is as varied, as their distribu- 

 tion is widespread ; some delighting in a tropical 

 heat, deep seas and coral reefs, and others in the 

 cool water of more northern latitudes and tem- 

 perate zones. It is with the Pearl oyster of the 

 Eastern Seas however that we are at present more 

 immediately Concerned. 



All true Pearl-bearers have one feature in 

 common, namely, the close resemblance existing 



