46 PEARLS [CH. 



these and also the young larvae which might develop 

 would be swept down by the current into the sea. 

 The eggs are kept inside the parent and develop into 

 peculiar larvae with tiny shell valves provided with 

 hooks. 



These young mussels are set free and clap their 

 shells vigorously. If by a happy chance they strike 

 some fish swimming in the water, they attach them- 

 selves and actually live partially embedded in the 

 tissues of the fish for some weeks. At the end of that 

 time they drop out as young mussels and take up 

 their normal life on the bottom. 



It will be advisable now to look more closely at 

 the conditions under which some of these pearl- 

 producing molluscs live. 



As it is beyond the scope of this little book to 

 discuss the homes of all the various pearl and nacre- 

 producing molluscs, it will be more satisfactory to 

 glance at the habitat of the Ceylon pearl oyster 

 as an example. 



The animals are found mainly on certain banks, 

 which are part of a submerged plateau in the Gulf of 

 Manaar, off the north-west coast of Ceylon. These 

 banks are known as " paars " — a name which implies 

 a hard bottom of any kind. They are situated in 

 depths of from five to about ten fathoms. 



The pearl oysters, like most of our molluscs, 

 require a particular kind of sea bottom. In addition 



