- any of the granules of lime, sand, etc., contained within a statocyst.
- an inclusion, as a starch grain, that by a change in position within the cells of an organ or part is assumed to cause a corresponding change in position of the organ or part.
- any of the granules of calcium carbonate occurring in a statocyst: movement of statoliths, caused by a change in position of the animal, stimulates hair cells, which convey the information to the brain by nerve fibres
- any of various movable inclusions, such as starch grains, that occur in plant cells and are thought to function in geotropic responses
