PEARL AND PEARL-SHELL EISHER/ES. 217 



Island, and familiarly known to the fishermen as the "old ground." Some forty vessels, luo-o'ers 

 of ten or eleven tons JDurden, were engaged in shelling operations on the area traversed by the 

 Albatross. The majority of these were boarded, the methods of working observed, materials 

 collected, and much practical information elicited from the divers. It was found in this connection 

 that all the medium pearl-shells — up to a diameter of seven or eight inches — were attached, in 

 a similar manner to the young ones already described, by a strong byssus or anchoring cable, 

 to a supporting fulcrum, this fulcrum consisting chiefly of the fragments of coral and shell, of 

 which the sea-bottom is here composed. The shells of larger size, nine or ten inches in dia- 

 meter, and of considerable weight, from 5 to 6 lb., were, in all examples examined by the author, 

 devoid of a byssus, and rested simply on their ocean-bed. A similar condition was observed 

 in several large shells which the author personally collected at extreme low tide on the "Warrior" 

 and other outlying coral-reefs. Such adult shells evidently require no cable to keep them anchored 

 in the tideway, their own weight insuring their stability ; this is in many instances further secured 

 by the luxuriant growth upon their exposed upper shells (usually the right valve) of heavy 

 Madrepores and other corals, such as the well-known Cup-corals, Tiirbinaria patiila and pclfata, 

 and innumerable varieties of sponges, shells, seaweeds, and other organic growths. Under such 

 a combined weight it would be altogether impossible for the animal to move, and the ques- 

 tion of its migratory habits, previously suggested, may, in face of the evidence here adduced, 

 be most distinctly answered in the negative. Many young shells, corresponding in every essential 

 detail with those referred to as having been obtained from the bottom of the Star of Peace, 

 were found adhering to adults. These young shells were saved alive, in company with a 

 series of matured specimens, for further investigation. 



The question will not improbably present itself why large pearl-shell was not found 

 adhering with the young ones to the bottom of the Star of Peace. The periodical cleaning 

 would necessarily prevent them from arriving at maturity in such a position. There is, at 

 the same time, every reason for believing that as soon as the3' attain to a certain size and 

 weight they literally slip their cable, and subside to the bottom of the water, or, probably, drift 

 with the current to a considerable distance. This capacity to detach themselves was fully proved 

 by the specimens kept in confinement. The presence of many an abandoned cable or byssus on 

 the older shells collected from the hulk further supports the foregoing interpretation. Mature 

 shells, from which the young ones adhering to the Star of Peace were probably derived, are 

 said to be abundant in the channel in which the hulk is moored ; but the currents are too strong 

 to permit of their being profitably worked. 



One of the most important purposes of the expedition was to ascertain, by direct experiment, 

 if it was possible to bring the pearl-shells in alive from the outer fishing grounds, and to rela}' and 

 cultivate them in the shallower, inshore, waters. The evidence hitherto adduced was not favour- 

 able to this scheme, the majority of the witnesses interrogated maintaining that the shells would 



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