110 NEW SOUTH WALES 
CHAPTER VII. 
Oyster Fisheries. 
Tue oyster fisheries of New South Wales are of immense value, and 
may become more so when we remember that “natives” are now ten 
guineas a bushel in London, It may soon be worth our while to export 
them, especially as ice would not be wanted. London pays between four 
and five million annually for oysters, and double the quantity might be 
sold. In Paris oysters are 12 francs the 100. The “ tinning of oysters 
might easily be conducted at a profit amongst us.” 
According to Dr. J. C. Cox (Pres. Lin. Soc., N.S.W.), who has given 
special attention to the subject, we have five distinct species of oyster 
in New South Wales ; these are—O. angasi, Sow., mud oyster, O. sub 
trigona ; Sow., drift oyster, O. glomerata, Gould, rock oyster, 0. cireum- 
suta, Gould, a rare species, O. virescens, Angas, also a rare species. The 
two last are of no commercial value, being rare, of small size, and 
difficult to remove from the rocks. 
The Mud Oyster. 
O. angast was, and is still by many regarded as only a variety of O. 
edulis, Linn., of European seas. The differences are that the valves are 
dentate at the margins. Mr. Sowerby says that the sculpture is less 
coarse, and Mr. Angas says that it is larger but more regular. Such 
distinctions will, however, hardly bear specific classification. It is found 
rarely in Port Jackson, though once very common, and it has grown 
very scarce in Tasmania. In Port Lincoln (Spencer’s Gulf, South 
Australia) it is still abundant. It was formerly abundant in New 
South Wales, as the kitchen-middens of the aborigines show; it was 
also formerly abundant in Pliocene times, as there are raised beaches 
in Victoria and South Australia entirely composed of the shells of 
this mollusc. It is undoubtedly one of the best if not the best of oysters. 
The species or variety O. rutupina, Jeffreys, is abundant in Tasmania. 
This is the “ native” or Colchester, or Carlingford oyster of Britain. 
The Drift Oyster. 
O. subtrigona.—Shell subtrigonal, oblong, or subquadrate, ponderous, 
rather narrow towards the umbones, broad at the ventral margin, quad- 
rate, margin strongly plicate, lower valve deep, greenish a as edged, 
slightly with purple, radiately plicate outside, concentrically banded with 
fawn and purple, hinge acuminated, sides crenulate near the hinge. The 
sculpture of the shell is bold and. large, and the square character of the 
ventral margin is striking. 
This is the Drift Oyster, so called because it is believed that its beds 
are shifted by the influence of storms or tides, It lies in beds consisting 
for the most part of free unattached individuals, or attached to masses 
of drift matter, or to each other by adhesions of the lower valve. The 
