be
opened containing several pearls detached, sometimes with one or more
adhering closely to the shell, and occasionally with pearls
conglomerated together in a shapeless mass. The oriental pearls are
seldom found of any colour but yellow and whke, and are usually of a
round or button form; whilst the American or Panama are generally
blackish or brownish, and mostly long and drop-shaped.
The number of fine and large pearls is, however, as may be supposed, very small.
The sea pearl-oyster, Meleagrina margaritifera, is
a large oyster of seven or eight inches in diameter, with very thick
shells, rather flat, and of a greenish-black exterior ; whilst the
interior is of a silver-white hue reflecting various colours, being,
in fact, the ordinary mother-of-pearl of commerce, too well known to
require further description here. Some idea of the quantity of this
material produced may be gathered from the fact that there are imported
into Europe annually some 15,000 tons; and, calculating the average
weight of a pearl shell, we have the astonishing number of from five 10
six million oysters which have been fished from the ocean.
The
principal pearl-fisheries are in the East,—on the west coast of Ceylon,
in the Bay of Manaar, in the Persian Gulf, and in the Sooloo Islands
(which lie between Borneo and Mindanao). Pearl-fishing is also carried
on in the Aroo Islands; near the island of Papua, or New Guinea; in the
Red Sea; in America, on both the
