Running-water Ancylus fiuviatilis eggs laid in March and July were allowed to develop in laboratory standing-water culture tanks and data collected on their subsequent development. Growth curves for height, length and width closely resembled each other, all following a double sigmoid growth curve. The curve for length was similar to that for aperture length of running-water Ancylus fluviatilis (Hunter l961b). Data collected on the egg development proved similar to those of previous workers, except that more eggs were laid than hatched from the egg capsules. Sedimentation affects development of eggs and young limpets and may be a controlling influence on limpet distribution. The maximum sizes attained by laboratory individuals were less than those for samples collected from river and standing water, however they copulated and laid viable eggs at these lower dimensions.