2iS THE GREAT BARRIER REEF. 



not survive removal from their native habitat, and that attempts previously made to transport the 

 shell had failed. In order to test the matter, several distinct methods were resorted to. Some 

 fifty e.xamples, varying from five or six to as much as ten inches in diameter, were placed at 

 the author's disposal by the different boats. The majority of these specimens were immersed 

 in two tubs of sea-water, on board the Albatross, the water being run off and renewed to 

 them every three or four hours. At night, when the ship was usually at anchor, the shells 

 were taken out of the tubs and placed in specially-constructed cages, composed of wire netting 

 stretched over rhomboidal wooden frames, this shape offering the least resistance to the current. 

 The frames, with their contents, were then lowered overboard, and secured by a rope until the 

 morning. A few specimens, some half-a-dozen only, were simply placed in a shady spot on deck, 

 sea-water being thrown over them at intervals. With a third equally small series, an experi- 

 ment was put into practice, identical with the method recentl}' reported to have been attended with 

 remarkable success in connection with the conservation of the American oyster for long periods 

 out of water. This method, known as " muzzling," consists of fastening the shell so tightly 

 together with wire that the liquids cannot escape. Thus treated, the oysters are said to survive 

 several weeks' isolation from their native element. All the pearl-shells treated in the several 

 manners described were brought into Thursday Island on the second day after their collection. Of 

 the examples confined in tubs of sea-water, renewed at intervals throughout the day, and lowered 

 overboard in frames at night, every specimen was preserved in perfect health. Of the number 

 simply placed in the shade on deck, sea-water being occasionally thrown over them, one-half only 

 arrived in good condition ; while the remaining half, being too exhausted to recover, fell a speedy 

 prey to crabs and predatory molluscs. A like untimely end befell all those examples upon which 

 the muzzling process had been practised. A subsequent study of the case last recorded showed 

 that the mortality was brought about through the liquid draining away entirely from the animals 

 through the byssal or pedal cleft, which retains its full development even in the adult shells, 

 by which a byssus is no longer secreted. A like explanation applies, in a less marked degree, 

 to the specimens left on deck, over which water was thrown at intervals. The above de- 

 scribed experiments clearly demonstrate that the mother-of-pearl shell, whilst of a much more 

 delicate constitution than the ordinary oyster, and very impatient of prolonged isolation from its 

 native element, might, with due care, and under conditions corresponding with those to which the 

 bulk of the specimens were submitted — namel}', continual immersion in sea-water, — be easily 

 transported in a living state from the outer fishing grounds to any desired locality. 



The next step taken was to ascertain the practicability of cultivating the pearl-shell brought 

 from the outer fishing grounds, from a depth of seven or eight fathoms, in the comparatively 

 shallow inshore waters. Some favourable-looking pools in the fringing coral-reef off Vivien 

 Point, immediately beneath the Government Residence of Thursday Island, were selected. These 

 pools, which were exposed only for a few hours during the lowest ebb of the spring-tides, proved 



