174 
THE NATIONAL GEOGRAPHIC MAGAZINE 
one institution alone has descended to us 
unchanged by the vicissitudes of 3,000 
years — the pearl fishery." 
In medieval times there was a very 
considerable literature of the Ceylon 
pearls and pearl fishery. In addition to 
frec[uent references in Arabic and Per- 
sian records of the eighth to eleventh 
centuries, the accounts of various Euro- 
pean travelers (one of whom was Marco 
Polo, 1 291) have come down to us and 
given glimpses that show how similar 
were the conditions then and now. The 
modern history of the pearl fishery, es- 
pecially under British rule, has been most 
elaborately recorded. 
THE PEARI. OYSTER 
It is hardly necessary to state that the 
pearl oyster of Ceylon, like the pearl oys- 
ters of other lands, is not an oyster at all. 
It is more nearly related to the mussels 
than to the oysters, and it dififers mar- 
kedly from the latter in having a byssus, 
or a bundle of tough fibers, by which it 
attaches itself to the bottom. 
There are pearl oysters and pearl oys- 
ters. There are the huge thick-shelled 
species of the South Seas, Australia, 
Philippines, and Burma, that are as large 
as dinner plates and weigh 3 to 4 pounds 
as they come from the water ; there are 
the small, thin-shelled forms of Vene- 
zuela, Japan, Persia, and Ceylon, that are 
only a few inches in diameter and weigh 
only a few ounces. 
The large pearl oysters produce the 
mother-of-pearl of commerce, which is 
so valuable that the fishery is profitable 
even when no pearls are obtained. The 
smaller mollusks have little value except 
for the pearls they yield. 
The maximum size attained by the 
Ceylon pearl oyster is only 4 inches, and 
the shells are so thin that they may be 
crushed between the fingers of an aver- 
age man. 
THE PEARE-OYSTER GROUNDS 
Pearl oysters are found on all parts of 
the coast of Ceylon, but exist in sufficient 
abundance to support an important fish- 
ery only in the Gulf of Manaar, wdiich is 
a large indentation between Ceylon and 
India, lying immediately south of the 
line of giant stepping-stones known as 
Adam's Bridge. 
The pearl oysters are more or less con- 
centrated on banks, which occupy a shal- 
low, level plateau, extending from the 
shore for a distance of 3 miles in the 
southern section to 20 miles in the north- 
ern and broadest part of the gulf. This 
plateau is bounded by the 10 or 12 
fathom curve, and falls away quite ab- 
ruptly, so that within a very short dis- 
tance of the fishing grounds we may get 
soundings of 100 fathoms, or even 1,000 
fathoms. The area of the pearling 
grounds is about 800 square miles. The 
bottom is for the most part sand, diversi- 
fied by outcroppings of calcareous rocks, 
which form flat or slightly inclined 
ledges, on which the pearl oysters 
grow. Aggregations of ledges constitute 
"paars," or banks, which centuries ago 
received names that are still applied. 
The largest and most important of 
these grounds is Cheval Paar, lying from 
9 to 13 miles offshore at a depth of 5 to 
85^ fathoms, and extending about 6^ 
miles from north to south and 4^/^ miles 
from east to west. 
UNCERTAINTY OF THE PEARE-OYSTER 
SUPPLY 
Probably the most remarkable feature 
of the Ceylon pearl fisheries is the ex- 
treme uncertainty of the supply of pearl- 
bearing oysters, so that from early times, 
and doubtless from the very beginning, 
the fisheries have been most unreliable 
and intermittent. A Dutch official, writ- 
ing in 1697, remarked that "the pearl 
fishery is an extraordinary source of 
revenue on which no reliance can be 
placed," and a British official in 1900 
said : "This statement holds good after a 
lapse of more than two centuries. In- 
deed, the periodical disappearance of 
oysters from certain of the banks, some- 
times for many years at a time, may be 
said to form one of the peculiar charac- 
teristics of the Ceylon fishery." 
It is a matter of record that during 
the 19th century there were only 36 years 
when fishing was possible. Mentioning 
only the longer periods of cessation, it 
may be noted that there were no fisheries 
in the years 1821 to 1828, in 1838 to 
