MUSSELS. 519 
precisely similar to those which, in a fossil state, form the earth on which 
the town of Richmond in America is built, THR well-known PEARL 
OvSTER is one of the most valuable of the shell-bearing molluscs, furnishing 
the greater part of the pearls that are set by jewellers and worn by ladies. 
The pearls are secreted by the animal in precisely the same manner as the 
nacre of the shell, and are, indeed, the same substance, formed into a 
globular shape, and disposed in concentric layers so as to give that peculiar 
translucency which is quite indescribable, but is known among jewellers by 
the name of “ water.” 
The Pearl Oyster does not produce its costly harvest under six or seven 
years of age, and it is therefore a matter of importance that the bed should 
be so managed that the young Oysters may be suffered to remain in peace 
until they have attained an age which renders them capable of repaying the 
expense of procuring them, and that no part of the bed should be harried where 
the Oysters are too small to produce pearls. 
The Oysters are now obtained by means of men who are trained to the 
business, and who can remain under water for a considerable time without 
being drowned. Each diver takes with him a net-bag for the purpose of 
PEARL OYSTER.—( Méleagrina Margarilifera.) MUSSEL. —(Mytilus Edulis.) 
holding the Oysters, puts his foot into a stirrup, to which hangs a stone 
weighing about thirty pounds, and after taking a long breath is swiftly carried 
to the bottom. He then flings himself on his face, fills his bag as fast as 
he can, and when his breath begins to fail, shakes his rope as a signal, and 
is drawn up together with the bag. 
WF. now come to the large, useful, and even beautiful family of the 
MUSSELS. 
THE EDIBLE MUSSEL, so common in the fishmonger’s shop and the coster- 
monger’s barrow, is found in vast profusion on our coasts, where it may be 
seen moored to rocks, stones, and fibres, alternately covered with water or 
left dry according to the flowing and ebbing of the tide. At some periods 
of the year the Mussel is extremely injurious as an article of food,though the 
_effects seem to depend greatly on the constitution of the partaker. Attempts 
have been successfully made to propagate the breed of Mussels; and the 
