Genus: Postoral kineties usually to left of oral poykinetids (Illustrated Guide, 1985).
Left edge is more curved than right edge; cytopharynx with numerous strong fibrils; ectoplasm with
numerous fusiform trichocysts; macronucleus oval; one to several micronulei (Kudo, 1966).
Frontonia elliptica Beardsley, 1902: Cell body 150-200 μm long; macronucleus ovoid, with a single micronucleus large, ovoid in shape; two contractile vacuoles present (Kahl, 1930).
Frontonia fusca (Quennerstedt 1869): Cell body 150-200 μm long; macronucleus ovoid, with a small micronucleu; a single contractile vacuole located at posterior half of the cell body (Kahl, 1930).