INSTINCT, INTELLIGENCE, AND USES 141 
Staffordshire has been recorded. Indeed, the Romans 
seem to have held the British freshwater Pearls in 
high estimation; while, according to Pliny, Casar 
dedicated to Venus Genetrix, and hung in her 
temple at Rome, a breastplate covered with British 
pearls, though these were possibly from the marine 
Mussel, which, as well as the Oyster, sometimes yields 
pearls. A large dull kind of pearl is. also got from 
Tridacna (the Giant Clam), and pink Pearls from 
the West Indian Fountain Shell (Strombus gigas), as 
well as from certain Turbinella. Fossil pearls of 
large size have, moreover, been found in our English 
chalk, being the product of the big Bivalve (Ino- 
cevamus) that occurs therein. Dr. Willey was 
fortunate enough to obtain a large pearl from a 
Nautilus shell in New Britain, this being apparently 
the only one known. 
For practical utilitarian purposes, however, the 
South Sea islanders make the most use of shells. 
They employ them as sinkers for their fishing nets 
in some cases as bait for Cuttlefish, manufacture 
fish-hooks, weapons, and even shaving tools out of 
them. 
In China and Japan the translucent shells of 
Placuna placenta are used for windows, and there is 
a “ Window-Shell” Oyster fishery near Trincomalee, 
Ceylon. 
The silky byssus of Pinna has been woven into 
gloves, caps, stockings, etc., and Taranto, in South 
