Helkesimastix faecicola Woodcock and Lapage, 1915. Cells ovoid or drawn out, 5-10 microns long and about two-thirds as wide as long. A single flagellum, 2-3 times cell length, inserts at or slightly below the cell apex, is attached along the length of the body and also adheres to the substratum as cells glided. The nucleus is central, and there is a single contractile vacuole towards the posterior. Cells are slightly flexible and the cytoplasm is sometimes drawn out along the trailing flagellum.
