A stinging or grasping organ in the outer cytoplasm of certain protozoans, especially ciliates, consisting of a threadlike or bristlelike filament that can be discharged suddenly from a minute capsule.

• 丝泡，线泡某些原生动物，尤指纤毛虫的外胞质中的叮咬或执握器官，由线状的或鬃毛状的细丝构成，可突然从一个小囊中释放出来