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SOFT-BODIED ANIMALS— THE MOLLUSKS 



into beautiful earrings. The most valuable pearls are found in the pearl 

 oyster which is a large oyster found in the West and South Pacific. 

 "Pearl diving." however, is not such a desirable occupation for you will 

 probably not find more than one pearl in a thousand oysters which may 

 have been collected under hazardous conditions. 



Photo by Winchester 



Fig. 19.7. Damage done to wood by the ship worm in 12 months' time. This little 

 bi-valved mollusk does great damage by boring through the wooden structure of ships 



and wharves. 



In Toba, Japan, a man named Mikimoto discovered a method of arti- 

 ficially introducing foreign bodies between the mantle and the shell of 

 the pearl oyster, thus stimulating pearl formation. About seven years 

 are required for the formation of a pearl of commercial value, so returns 

 on investment are somewhat slow, but certainly worthwhile when they 

 come. Mr. Mikimoto has developed a great industry from his discovery 

 and has become quite wealthy. He sometimes gives dinner parties at 

 which he serves oysters in the shell. The luckier guests come away with 

 one or more pearls as souvenirs of the occasion. 



