CHAP, ix.] HABITS OF THE PEARL-OYSTER. 401 



" The natural history of the edible oyster is now so well 

 understood that its culture on artificial beds is in successful 

 progress in many places on the coasts of both England and 

 France ; but it is one thing to breed and fatten edible oysters 

 for the palate, and another to breed the pearly mollusc of 

 Ceylon to produce pearl. 



" That which is commonly called the pearl-oyster of the 

 Gulf of Manaar is classed by naturalists with the mussel in 

 consequence of its shells being united by a broad hinge and 

 its having a strong fibrous byssus with which it attaches itself 

 to the shells of others, to rocks, and to other substances. It 

 had long been believed that the fish in question had not the 

 power of locomotion, nor of detaching its byssus from the sub- 

 stances to which it adhered ; but in the year 1851 it was 

 satisfactorily ascertained that when it had become detached 

 it possessed the power of extending its body from within its 

 shells and of creeping up the inner side of a glass globe con- 

 taining sea-water. It was, however, left to the late Dr. Kelaart, 

 when employed by government as a naturalist to study the 

 habits of the fish, to discover that, although it could not detach 

 its byssus from the rock to which it adhered, it had the power 

 of casting off from its body its entire byssus and of proceeding 

 to some other spot, and there, by forming a new byssus, of 

 attaching itself to any substance near to it. It is therefore 

 now believed that the Manaar pearl-fish has the power of 

 changing its position, and this may account for the disappear- 

 ance of large quantities from the sandy places on which the 

 brood sometimes settles ; but it is by no means so clear that 

 these fish are able to drag their shells after them over the 

 rugged surface of coral rocks. 



<c I have already stated that the produce of the pearl-fish of 

 the Gulf of Manaar varies in richness of colour, in the size of 

 the pearl, and the quantity of its yield, according to the nature 

 of the ground on which it rests, or of the food which that 



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