[Ciliophora] Membrane-bound, subpellicularly located extrusible body of various, probably nonhomologous types (e.g., cyrtocysts, mucocysts, pexicysts, toxicysts, trichocysts). Discharge typically occurs after chemical or mechanical stimulation, used to capture prey or for defence (Ci 5B ), (Ci 7A ).

Alternative forms for Extrusome : extrusomes, Kinetocysts.