Table 1. Numbers of oyster spat and spat scars counted on different dates on the inner surfaces of 20 



shells from weekly bags, Tred Avon River and Broad Creek, Md. , 1961 



(Tred Avon River and Broad Creek stations tended fortnightly after Aug. 22) 



Table 2 Numbers of oyster spat and spat scars counted on different dates on the inner surfaces of 20 



shells from weekly bags, Tred Avon River and Broad Creek, Md., 1962 



•■■ Bag lost. 



