perfect
in quality. The shell in which it was found was only knee deep in
water, and the Pearl is probably the finest which the Australian
fisheries have hitherto produced.
The
following instances of the development of blisters, will assist the
reader in the study of the growth of shell and Pearls. In 1883, a young
shell not one third the average weight and size, was found with two
blisters within. In each of these a small stone was seen uncovered
in'part, and the rest thinly covered over with a pearly film, the
stones being plainly discernible on all sides.
In
another shell a blister was found more than one inch in height from the
plane of the shell. This blister was full of black mud, and the pearly
covering was not more than ^jth part of an inch in thickness.
In
1882, on board the " Dawn," a small protuberance was noticed in a
shell on the point of the inside part of the hinge. A little of the
outside surface of the shell was scraped away, and the round surface of
a large shell was discovered ; the hinge of the shell was then cracked
with a hammer and chisel, and eventually a very fine coloured and
fairly-shaped Pearl weighing 80 grains was extracted.
In 1883, on board the same ship, another
