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REPORT ON OYSTER CULTURE 



Ostrea rufa. 



Ostrea columbiensis. 



magaritaca. 



lacerans. 



gibbosa. 



bicolor. 



elliptica. 

 angulata. 

 echinata. 



multistriata. 



callichora. 



glaucina. 



stellata. 



sinensis. 



prismatica. 

 lamellosa. 



turbinata. 

 crista galli. 



tincinata. 

 raricosta. 



hyotes. 

 radiata. 



senegalensis. 



orientalis. 



rosacea. 



inegadon. 

 pes. tigris. 

 lincolnii. 



chemoritzii. 



pyxidata. 



Natural History of the Oyster. 

 For the better elucidation of the subject with which we are 

 charged, we deem it desirable in the first instance to give a brief 

 account of the oyster itself. 



Hanly gives the following varieties of the oyster in his catalogue 

 of bivalves : — 

 Ostrea edulis. 



hippopus. 



adriatica. 



cochlear. 



cristata. 



gallina. 



lingua. 



tulipa. 



scabra. 



rostralis. 



parasitica. 



denticulata. 



excavata. 



mytiloides. 



sinuata. 



trapezina. 



Ostrea edulis is the oyster of commerce in this country. 



In all climates, and in all its varied species, the oyster is 

 supposed to be hermaphrodite, and its chief characteristics appear 

 to be the same wherever it is found. 



The precise manner in which the impregnation of these molluscs 

 is effected is yet an unsolved enigma. 



There are various theories extant upon the subject, which have 

 all been, more or less, under public consideration and discussion. 

 One of the latest is that put forward by Dr. Kellart, which is 

 supported by Mr. G. W. Hart, one of the members of this com- 

 mission, viz., that there is a mutual fecundation partaken of by all 

 the individuals composing an oyster-bed — a general emission of 

 spermatozoa taking place at a period somewhat prior to the for- 

 mation of ova in the ovaries. 



If this view be correct, it would serve to explain much of what 

 has hitherto been the great casus belli between those who hold the 

 opinion that the present scarcity of oysters is caused by failure of 

 spat, and those who attribute the failure to over-dredging. Viewed 

 in this light it would appear that the aggregation of oysters into 

 beds is a provision of nature to effectuate this mutual impregna- 

 tion, and that when an oyster bank has been so greatly dredged 

 that the component individuals upon it are at great distances from 

 each other, the reproductive powers of the bed may be almost 

 entirely destroyed, although dredgermen may still obtain sufficient 

 oysters to remunerate them for their labour in seasons when prices 

 are high. Unless the tide or current in such cases brings the 

 spermatozoa within reach of adjacent oysters, a bank so reduced 

 ultimately (and quickly) dies out to the great astonishment of 

 those fishermen who can testify (and that truthfully) that there 

 has always been oysters upon it, and that it was not in their opinion 

 exhaustively dredged. The breeding season may be said to com- 

 mence with the disappearance of the letter R from the nomen- 



