U. S. B. F. — Dec. 951. 



Fig. 3 — Adult oysters spawning naturally on tray in large spawning tank. 



Fig. 4. — Artificially propagated oyster spat collected on sea-scallop shells for observation. Lower 

 row, spat 7 weeks old; upper row, spat 3 weeks old. The three shells on ihe left in the upper 

 row were kept in the rearing tank while the others were placed in the harbor. 



