Percolomonas descissus (Perty, 1852) Larsen and Patterson, 1990. Cells are ovoid to pyriform and about 9 to 15 microns long with a big ventral groove, which extends from the anterior end to half or three quarters the way down the cell. There are four flagella, which insert subapically and are directed ventrally and posteriorly. Three flagella are similar in length and one long flagellum is about 1.5 - 2 times the length of the cell. All flagella usually beat together and close to the groove. The longest flagellum appears to be acronematic. The nucleus is situated behind the apex of the cell. The cells swim by rotating movement and may attach to the substrate by the longest flagellum. The cells have typically with many food vacuoles. Cytoplasmic strands are seen in the posterior end of the cell. Observed more usually from anaerobic sources.
