During experiments by the U.S. Fish and Wildlife Service and the Maryland Conservation Department on the fouling of oysters in Chesapeake Bay, shells exposed on the bottom were examined for folliculinids. Observations in the upper part of the Bay, at about 15 stations in 9 to 20 feet of water along some 40 miles from Choptank to Tochester from mid-May to mid-October, showed that settling began the last week of June, or occasionally mid-July, and continued until the last week of September; generally there was a decline in density during August and occasionally an increase in September with cooler water. Further down the Bay, shells were exposed off the mouth of the Patuxent River on "Parker Moore" bar in depths of 6 to 16 feet of water during 1944-1947; 1417 shells were examined, of which 243 bore folliculinids, with a much higher percentage of settling in deeper (26%) than in shallow water (6%). Exposures of shells on bottom were irregular, making comparisons of seasonal settling difficult, but settling did occur, though with considerable irregularity, during both winter and summer in each year. It is inferred that folliculinids are both sedentary and migratory at all times of year in the Chesapeake. Table I gives the data.