portrait

Description:

Strobilidium caudatum (Fromental, 1874) Foissner, 1987, a spirotrich ciliate. Synonym of S. gyrans.The cell body is goblet shaped with a complete circular (closed type) wreath of membranelles at the anterior end. The adoral zone of membranelles is well seen in this image. Unlike Strombidium, there is no posterior lorica. There are five very reduced rows of somatic cilia which converge at the posterior end of the cell to form a tight spiral as seen in this image. The terminus of the cell secretes a mucus thread allowing attachment to the substrate. Once attached the cell moves back and forth in pendulum fashion for a time then breaking free to swim away very rapidly. The oral aperture is eccentrically located within the adoral zone of membranelles. A peripheral contractile vacuole is seen posterolaterally in this image. Feeds on diatoms, flagellates and probably bacteria. From freshwater pond near Boise, Idaho. Brightfield illumination.