GAMETOGENESIS AND SPAWNING OF THE EUROPEAN OYSTER, O. EDULIS, IN WATERS OF MAINE

¹ U. S. Bureau of Commercial Fisheries, Biological Laboratory, Milford, Connecticut

1. Active spring gametogenesis begins in May.

2. General spawning begins approximately during the second or third week of July and continues until about the end of August.

3. Because of short, cold summers, usually only one sex phase is completed by an individual oyster.

4. Resorption of gonads is carried principally by phago-leucocytes which enter the follicles not through the follicular walls, as in American oysters, but directly through the blood vessels.

5. Resorption of gonads may continue throughout the winter and early spring.

6. Differences in conditions of gonads of O. edulis planted in Boothbay Harbor suggest that the original group was not composed of a homogeneous population, but consisted of different physiological races.