[page 6]
varieties of which are found in tropical regions all over the world. River
pearls, such as are found in the Little Miami River, Ohio, and in the
Mississippi River near Muscatine, Iowa, are generally produced by the
Unio Margaritiferus. Once in a while pink pearls are produced by the
great conch or fountain shell. Black pearls of great value are found in the
pearl oyster inhabiting the Gulf of Mexico. (1)

"Pearling" has become such an important industry in many lands
that governments have adopted protective regulatory laws. In India
these fishing grounds are under the control of Government inspectors.
During the season, which begins about the middle of March, fleets of
boats leave port at midnight and reach the oyster beds at sunrise. When
the boats are in position over the banks a signal gun is fired and work
begins. (1)

The real Indian diver recognizes the risk he runs in these shark-
infested waters and, to protect his life, resorts to a very ancient method.
The sharks must be charmed. Every boat carries a shark charmer and no
Indian diver will chance a dive without the incantations of this member
of his crew. For additional protection the diver carries an ironwood
spike but, despite these precautionary measures, he is usually a short-
lived man. (1)

The men work in pairs, one remaining on board to watch the
signal cord or rope. The diver, with his spike of ironwood and a basket
for the oysters, is let down by this signal rope to which a 40-pound stone