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ECONOMIC ZOOLOGY 



tin from can factories; scallop shells; and especially oyster shells. New 

 beds may be started by spreading the cultch over the bottom at the 

 breeding season and then distributing "wild" oysters, that are about to 

 spawn, over the cultch. After the spat has "set" over the cultch and 

 has grown into "seed" oysters of an average size of half a dollar, the 

 cultch may be collected, broken up and spread over the bottom again 

 to prevent the growing oysters from crowding each other, Figs. 29 



PIG. 30. A bed of well-shaped, ^marketable oysters. 

 Grave, from Brooks, The Oyster.) 



X Ko- (Photograph by 



and 30. This is the general method of oyster culture as carried on in 

 many places. Of course, it necessitates a survey of all the oyster 

 grounds, just as farms are laid out, in order that dishonest dredgers, 

 of which there are many, may not reap where others have sown. It is 

 also obviously more troublesome than harvesting the "wild" crop, 

 but unless some sort of culture be adopted the wild crop will inevitably 

 become exhausted. The most serious difficulty in such cases always 



