scar.
The mother-of-pearl under the epidermis at the thick or hinge end is
quite iridescent, and the lines which make the color play are plainly
discernible under the loup.
The
largest and finest pearls, also the greatest number, are found usually
in distorted shells. This has given rise to the idea that they are a
symptom of disease in the fish, but having in mind the functions of the
three zones of the creature's mantle by which they supply separately
material for the epidermis, middle shell and lining, one may conceive
that if, by some extraordinary cause, the secretions of one of these is
largely withdrawn from the natural channel, the losing part of the
shell would warp the normal growth of the others to its own dwarfage.
When
the nacre grows to a pearl, contrary to the intent of nature, instead
of a lining for the shell endeavoring to keep pace with the growing
oyster, the full-growing exterior is distorted in accommodating itself
to the undersized lining. In view of the fact that an oyster sometimes
contains a large number of pearls (one shell in New Caledonia contained
256) the diversion of
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