CHAPTER XII. 



PEARLS, AND MOTHER-OF-PEARL. 



" Orient pearls at random strung." 



j]Y a natural transition we pass from Oysters to 

 PEARLS, these beautiful jewels having been 

 long associated with the popular molluscs in 

 the popular mind. Pearls, as well as mother- 

 of-pearl, are the product of certain molluscs, fresh-water 

 and marine, such as the pearl-oyster, the pearl-mussel, 

 the haliotides, and the patellae. The finest, however, are 

 those obtained from the so-called pearl-oyster, the Avi- 

 cula, or Meleagrina margaritifera. 



This mollusc, like the oyster proper, is a bivalve, and 

 a lamellibranchiate mollusc of the family Aviculidce. It 

 owes its generic name, Avicula from avis, a bird to the 

 peculiarity that, in certain species, the animal, when its 

 valves are open, presents a vague resemblance to a bird 

 with outstretched wings. Hence it has sometimes re- 

 ceived the poetical appellation of " the swallow." It is 

 usually found congregated in great numbers, attached to 

 submarine rocks at a considerable depth in all tropical 

 waters. Pliny affirms that the finest pearls are found in 



