statocyst

statocyst (noun; Greek statos, fixed; kystis, bladder): An organ of balance found in many invertebrates, variable in structure from an open canal, vesicle, or closed chambers composed of one to many cells (lithocytes), that contains a concretion of granules of sand, lime, diatom shells or quartz grains (statolith), or capsules of ciliated cells enclosing a fluid with one or more statoliths suspended within

See also: otocyst.