(also Simonsiella), a genus of microorgan-isms of the family Oscillospiraceae. They are long, rod-shapedor filamentous (15–30 nanometers X 3 nanometers), slightlycurved mobile organisms with numerous flagella. They are di-vided by septa into short cells. They do not form spores and areweakly gram-positive. These organisms reproduce by segmenta-tion into two or three parts or more called hormogonia. They arefound in water, rotting organic matter, intestines of insects, cat-tle manure, and human feces.