” 
80 CONCHOLOGIST’S COMPANION. 
noticed, form several regular lamellze, resembling the 
coats of an onion, or different strata of bezoars, 
though considerably thinner, and more delicate in 
their construction. Loose pearls are often found 
within the shelly covering of the Mytilus; but when 
this occurs, they have been undoubtedly rejected 
from the stomach of the animal, and have fallen 
into the cavity of the shell; whilst such as are 
fixed, most probably owe their origin to some inte- 
rior roughness. 
The exterior of the Mytilus Margaritiferus gen- 
erally indicates the value of the gem which it 
contains. Such as are varied and incrusted with 
thick calcareous substances, and with zoophytes of 
different kinds, enclose the finest pearls; those on 
the contrary, which present a smooth unbroken 
surface, have only begun to form these valuable 
secretions, and are sometimes entirely without them. 
The observation of this curious fact, most probably 
suggested the first idea of forcing the Mytilus to 
produce pearls. It was known in the first centuries 
of the Christian era, and acted on by the ancient 
people who inhabited the coasts of the Red Sea, as 
we are informed by the philosopher Apollonius. 
‘‘The Indians,” said he, ‘‘ dived into the sea after 
they had rendered it calm, and perhaps clearer, by 
the pouring in of oil; they then induced the Muscles, 
