Infraciliature, left side

Description:

Portrait of the armophorid ciliate, Caenomorpha medusula (Perty,1852). The colorless pellicle is rigid and twisted to the left. The anterior is broadly rounded and umbrella-like with a long posterior spine. Somatic ciliature is reduced to 2 curved rows of thigmotactic cirri on the left side of the anterior dome (seen well here). The peristome spirals around the long axis, bordered anteriorly by a perizonal stripe of cilia and posteriorly by an adoral zone of membranelles. The cytostome situated at the posterior end of the peristome. There are 3 or 4 spherical macronuclei; 1 posterior contractile vacuole is located at the base of the spine . The cytoplasm contains multiple endosymbiotic methanogenic bacteria. C. medusula is found in anaerobic habitats. C. medusula is distinguished fro other species in the genus by its shape and by its two anterior cirral files (other species have only one). Collected from sapropelic bottom sediments of a slow-flowing freshwater stream near Boise, Idaho January 2005.Stained by the silver carbonate technic (see Foissner, W.Europ. J. Protistol.27,313-330;1991) Brightfield.