182 UTILIZATION OP MINUTE LIFE. 



case with some of the larger Gasteropoda and 

 Bivalves of the Southern seas. 



There exists a peculiar kind of cameo termed 

 the Chinese cameo, or pearl cameos. The process by 

 which they are made has lately been discovered : 



" The Ningpo river abounds in oysters, which the 

 natives take up when they have grown to a certain 

 size. The shells are then partially opened, care 

 being taken not to injure the animal, and moulds 

 bearing the required design are introduced be- 

 tween the valves. The shell is then allowed to 

 close, and the oysters thus operated upon are 

 placed in beds prepared for their reception. After 

 remaining there for some months, they are again 

 taken up and opened, when the mould is found 

 beautifully crusted over with mother-of-pearl ; it is 

 then dexterously detached, and made into various 

 ornaments." 



We will now turn our attention to the Mollusca 

 which produce pearls. Of pearl " oysters," as 

 they are generally called, or rather pearl mussels 

 for the animals that furnish us with these jewels 

 are more closely allied to the mussel than to the 

 oyster there are two descriptions, namely, those 

 which inhabit rivers or fresh water, and those which 

 live in the sea. 



We shall have to consider, then, the fresh-water 

 pearl, and the marine or Oriental pearl ; but as the 



