PEARL FISHERY.

141

in the Report upon the Ceylon Pearl Fishery now being
published in London bv the Roval Society.

Tampalakam Pearls.—A fishery for an inferior variety
of small pearls was long carried on in an extensive shallow
and muddy-bottomed inlet known as Tampalakam bay, a
few miles to the south-east of Trincomalee, on the northsagt
 coast. The oyster yielding these pearls is the welltnown
 window-pane oyster (Placuna placenta), which has
sarned its name from the use to which the Chinese in some
sarts put its flat translucent shells. In texture and in

SHELL-HEAP OF WINDOW-PANE OYSTERS, LAKE TAMPALAKAM.
appearance the shells bear a superficial resemblance to white
mica and want entirely the lustrous and dense inner coating
>f opaque mother-of-pearl characteristic of the true pearl
oyster.
As gems, Placuna pearls have little value, wanting as
;hey are in lustre, symmetry, and hardness. As with the
chank industry, so with this, it depends for its being upon
Hindu customs, such of the wealthy of India who are
betel-chewers esteeming the prepared lime or *chunam,”
which is an essential ingredient in the mixture chewed,