exceeding
in size the palm of a man's hand, and though it exhibits the most
brilliant nacre, and produces fine small Pearls, its shell has but
little market value as mother-of-pearl, being worth only from 20s, to 30s. per ton. On the other hand, the Me-leagrina margaritifera is
considerably larger and thicker, and yields the most valuable
mother-of-pearl, as well as the finest Pearls, although these are not
numerous. Indeed so pronounced are the differences between the two
species in this respect, that the former might, with propriety, be
called the " Pearl," and the latter the " Shell " oyster.
The number of Pearl-producing molluscs, however, is by no means confined to the Aviculida: they
are on the contrary members of a very large group, which frequently
differ from each other in almost every other possible respect : indeed
their general configuration is as varied, as their distribution is
widespread ; some delighting in a tropical heat, deep seas and coral
reefs, and others in the cool water of more northern latitudes and
temperate zones. It is with the Pearl oyster of the Eastern Seas
however that we are at present more immediately concerned.
All true Pearl-bearers have one feature in common, namely, the close resemblance existing
