FISH AND FISHERIES. Ill 



beds are always in moderately deep water, and never uncovered by the 

 tide. It is the common oyster of New South Wales and Brisbane, and 

 is largely exported to the neighbouring Colonies. 



It is commonly supposed, says Dr. Cox, that this species and the rock 

 oyster are identical, and -with this view many pei-sons have gathered 

 rock oysters and planted them in beds with a view to their cultivation. 

 He maintains, however, that this only leads to loss, for if this species is 

 placed in positions where it is uncovered by every tide, it speedily dies ; 

 but if properly cultivated on the beds it usually inhabits, it will become 

 a most important article of food. 



Mr. Oliver and many others maintain that the drift oyster will 

 flourish well if left under the same conditions as the rock oyster, that is 

 where it is uncovered by every tide. The first-named gentleman tells 

 me that he has tried the experiment, and succeeded in rearing a fine lot 

 of drift oysters. On the other hand, rearing rock oysters in drift 

 oyster beds is an experiment successfully and frequently effected by 

 every oyster grower*. Altogether the evidence preponderates in favour 

 of the theory that 0. suhtrigona and 0. glomerata (that is the so-called 

 rock and drift oysters) are the same species under diff'erent conditions. 

 With ordinary care and attention they may be grown in deep or tidal 

 waters. 



The Rock Oyster. 



0. glomerata, or Rock Oyster. This is the kind which is found so 

 abundantly adhering to the rocks on all the east coast of Australia. Dr. 

 Cox regards it as distinct from that which occurs so abundantly on the 

 Queensland coast, especially on the coral reefs, where all the outstanding 

 blocks of coral (nigger heads) are covered with them. This is Ostrea 

 mordax, Gould. Having given the subject every consideration in 

 travelling along the east coast I cannot regard the species as distinct. 

 No definite specific distinction can be found when large numbers of species 

 are examined. This oyster is generally found adhering to rocks which are 

 not always covered by the tide. It is often beautifully frilled, and of a rich 

 j:)urple colour. " If," says Dr. Cox, " individuals of this species ai'e placed 

 in proper trenches or in positions where clear fresh sea-water will flow 

 over them at each tide, they thrive and fatten to an extent which makes 

 them a valuable article of food and an important commercial product, 

 and by placing low stakes of wood or other material for the spat to adhere 

 to when emitted from the mother shell, they are easily and successfully 

 propagated. But when placed in such positions, especially on mud flats 

 which are uncovered by every tide, they are liable to the attacks of a 

 number of other molluscs, and unless the water which flows over them 

 is pure, and free from decomposed vegetable matter and from grit, they 

 suffer from the irritation caused by such particles, some discolour 

 and waste and others die." To this species is also to be referred 0. 

 cacullata of Born. The variety is merely an overgrown form of the 

 hinge very common on the coral reefs. 



A Royal Commission was appointed in the latter end of the year 1876 

 to take the important question of the Oyster Fisheries into consideration, 

 and a very excellent Report from that Commission was brought up and 



