THE TROPICAL 
AGBICULTUKIST. [Jan. 1, 1904. 
A UHAT WITH MR. JAS. HORNELL. 
THE PEAKL FISHING— DREDGING FOR TEARIS— 
THE FISHING INDUSTRY OF CEYLON ; 
WORK AT GALLE, «&C. 
Mr Jas ' Hornell, Marine Biologist at Galle 
who, somelime ago, waa unwilling to express 
his views on tiie experiment recently made to 
dredge for pearls, has just been seen by our repre- 
sentative and was in a position this time to furnish 
particulars as to the same, and also to give some 
idea of the pearl fishery, and the fishing industry of 
Ceylon. Mr Hornell's journsy to the North was 
specially made to find the creature in which 
the oyster parasite came from, and he was suc- 
cessful in finding this out. He found out that 
through the oyster the parasite entered what was 
called the trigger fish which was a minor enemy 
of the oyster and ate it, and by so doing the parasite 
in the oyster was transferred to the stomach of the 
fish. The parasite became adult in some creature 
that fed the trigger fish and this was found in the 
intestines of a ray (Tryqon). The parasite had 
to die before a pearl could be formed in the oyster. 
These parasites were essential to the production of 
pearls. The greater the number of parasites, the 
greater the number of pearls. Speaking about the 
DREDGING OF PEARLS 
in future Mr Hornell said that the recent Sredging 
experiment produced very satisfactory results and 
there was no reason why Government should not 
adopt it. The net is capable of holding about 900 
oysters at a time. The width at the opening of the 
net is 3 feet and, therefore, the portion of land 
dredged at a time will be 3 feet in width, 
THE FISHING INDUSTRY. 
"The fishing Industry of Oeylon, Mr Hornell, 
what is your idea of it ?" — "It is at present carried 
on according to primitive methods. The caste 
system limits development, but in spite of this the 
fisheries of the Island furnish great supplies of 
excellent fish. Comparatively little fish curing or 
salting is carried on, though Government has 
done much to encourage it by establishing fish- 
curing yards. A trade distinct from that of 
ordinary fish-curing is the preparation for the 
Chinese Market of dried sharks' fins. In the 
Northern Province an extensive trade is done in 
the ar,ticle. 
THE PEARL FISHERIES. 
Alluding to pearl fishing he said:— "The Dutch 
had several good fisheries and the British too had 
very good pearl harvests during the first years of 
their occupation. The fisheries during the first 
37 years were regular, but after that they became 
erratic. In 1815 as little as £584 was got from 
a pearl fishery. The best beds are where a coarse 
grit sand is interspersed with frequent outcrops 
of flat-surfactd rock or where many loose 
fragments of stone or of dead coral (cultch) 
are scattered over the surface of the sand. In such 
situations, the oysters do not become overcrowded 
and with sufficiency of food come early to the 
pearl-producing stage. Rocky banks, which are 
crowded with spat, seldom bring oysters to profi- 
table maturity — over-crowdiug producing stunting 
of growth, disease and premature death. The 
Chief Agency in the irregularity of tlie pearl 
fishing in Ceylon has been found to be, from in- 
vestigations made by Prof, ilerdnian and myself, 
the tendency of spat to fall upon unfavourable 
ground, where — if exposed to the full violence of 
monsoon storms — it is liable to be smothered by 
overwashes of sand ; or where, if the ground 
is 'continuously rocky, the oysters eventually 
become stunted by the shortage of food in- 
duced by overcrowding. The chief remedies 
proposed are 
THE TRANSPLANTATION OF SPAT 
from unfavourable to favourable ground and the 
thinning out of overcrowded beds. The old idea 
of pearls being due to the irritation caused by an 
intrusive grain of sand was proved untenable, 
although three instances of this 
SAND ORIGIN OF PEARLS 
were found among several bundled instances 
traced to other causes. There are two 
chief classes of pearls, namely " Orient " pearls 
or "fine" pearls of commerce and those 
known as " seed pearls," Orient pearls were 
discovered to be due to [irritation caused within 
the tissues of the pearl oyster by the presence of 
the dead bodies of the spherical larvae of a small 
tapeworm (Tetrarhynchus) which often infects the 
Ceylob Pearl Oyster in considerable numbers. 
Pearls are most numerous in oysters which have 
long beeix infected ; where the worms are 
oldest and so are most liable to die ; 
the living worm does not produce pearl 
formation. The inferior class of seed pearls is due 
to the formation of crystalline bodies, analo- 
gous to gall stones, within certain muscles of the 
oyster. Later, they become through irritation, 
the nuclei of pearls, coats of nacre, similar in 
composition to the mother-of-pearl lining of the 
shell itself, being deposited concentrically around 
and thus the pearl increases in size. " Orient " 
pearls are similarly formed of successive coats, 
differing solely in the character of the nucleus of 
the originating irritant body. There are also an 
inferior variety of pearls, the Tamblegam pearls 
found in the bay of the same name. The oyster 
yieldinti them is the window-pane oyster. They 
resemble white mica very much in appearance. "Can 
SPONGES 
become an industry in Ceylon?" — "They occur 
abundantly in localities around Jaffna and in Trin- 
eomalee harbour. A few men actually fish them in 
small quantities, but as an industry it has no value. 
At Trincomalee they are found growing profusely 
stones in shallow water, [ have filled a basket 
^ith about a dozen or so of fine specimens within 
(jl^e space of five minutes," 
MARINE WORK AT GALLE. 
" How do you find the Galle Harbour for your 
work as a Marine Biologist, and does it afford the 
facilities you require ? " — " I think no better site 
for such an institution could have been chosen 
in the tropics. The place is rich in all that is of 
interestto a Zoologist interested in Marine fauna. 
The lagoons of the fringing coral reef around the 
Fort abound with corals, and alcyonarians, sea 
urchins, star fishes, sluggish holothuriums, and the 
giant synapta beselii, which extends six feet of 
snake-like body. Balanoglossus can be had in 
numbers. Sponges form extensive crusting growths 
often gaudily coloured. The Galle harbour is njosb 
ej^cellent for the study of corals, and Zoologists 
vKiting Ceylon will find many facilities for 
research at the Marine Laboratory." 
