Genus: Oral cavity tubular; deep groove spirals at least once around body (Illustrated Guide, 1985).
Like Colpodabut peristome is curved; body somewhat twisted
(How to know the protozoa, 1979).
Tillina canalifera Turner: 150-200 μm long; resembles magna but macronucleus ellipsoid, about 1/3 the body length; a contractile vacuole with 7-9 long permanent collecting canals; cytoplasm with long refractile rods (Kudo, 1966). 130-200 μm long; like Colpoda, but peristome is curved, leads to a large vestibule, which leads to the true mouth; body twisted (How to know the protozoa, 1979).
Tillina magna Gruber: 180-200 μm long, up to 400 μm long; macronucleus oval to rod-shape; micronuclei vesicular, variable in number; a contractile vacuole terminal with 6 long canals (Kudo, 1966). To 400 μm long (How to know the protozoa, 1979).