Simpson et al., 1997. Cells with adhering paired nuclei and encountered as flagellated and non-flagellated amoebae or cysts. The flagellated cells are 7 to 25 microns long (average 11.6, n=14), and have a single pair of nuclei. The length of the flagellum is highly variable but usually considerably longer than the cell body. The cytoplasm appears smooth and homogeneous although granules and endoplasmic reticulum were sometimes observed. The non-flagellated forms are 12 to 70 microns (average 41.9, n=8) long and have one to five pairs of nuclei. Cysts are roughly spherical and are 12-13 microns across, with a single pair of nuclei. During swimming the flagellum is directed anteriorly and as with other pelobionts studied here, generates tip-to-base waves. Cells, flagellated and non-flagellated, may glide slowly in an elongate configuration.