110 NEW SOUTH WALES 



CHAPTEE YII. 

 Oyster Fisheries. 



The 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 " turning 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 — 0. angasi, Sow., mud oyster, 0. sub 

 trigona ; Sow., drift oyster, 0. glomerata, Gould, rock oyster, 0. circimi- 

 suia, Gould, a rare species, 0. 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. 



0. angasi was, and is still by many regarded as only a variety of 0. 

 editlis, 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 0. rutupina, Jeffreys, is abundant in Tasmania. 

 This is the " native" or Colchester, or Carlingford oyster of Britain. 



The Drift Oyster. 



0. suhtrigona. — 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 white, 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 strikincf. 



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 



