Trepomonas (tree-poe-moan-ass) agilis Dujardin, 1841. Cell is ovoid, but S-shaped in cross section and is about 11 microns long. Two nuclei are located anteriorly. Two groups of flagella are inserted laterally at the end of each groove: two long flagella and six short flagella. The length of the long flagella was not measured, but the short falgella are less than half the cell length and lie in the grooves. The cell moves by swimming. Contractile vacuoles are seen. Rarely observed.