Dorsal silverline system (double patella type)of the hypotrich ciliate, Euplotes patella (Mueller, 1773) Ehrenberg, 1831.Collected from a freshwater irrigatio ditch near McCall, Idaho. May 2005. Dry silver nitrate stain (see Foissner, W. Europ. J. Protistol., 27:313-330;1991).Brightfield.