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).
Species: Cell body 150-600 μm long; anterior half of the cell broader than posterior half; posterior end slightly pointed; two ovoidal micronuclei; a single contractile vacuole (Kahl, 1930).
Frontonia marina, stock 40-1a, stained with Azure C,
cell body μm long, μm wide,
macronucleus spherical or ovoid, with two micronuclei present,
x 640, Uruguay, 1999 by Y. Tsukii
16 μm 32 μm 63 μm; x 640
Frontonia marina, stock 40-1a, cell body μm long, μm wide, micronuclei relatively large, x 640, Uruguay, 1999 by Y. Tsukii
31 μm 63 μm 94 μm; x 640