“The Gulf of Manaar pearl-fisheries having again ceased to be productive, the government of Ceylon appear to be impressed with a belief that further information is needed respecting the habits of the pearl-oyster, and that it may be desirable to obtain the services of a naturalist to study and report on the best means of insuring a continuous revenue from pearls. “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 substances 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 containing 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 disappearance 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.