Family: Cirral file ends dorsally; body long, tapered at rear (Illustrated Guide, 1985). Genus: Body ovoid, tail region absent (Carey, 1992). Same as the family (Illustrated Guide, 1985). Body elongate, cylindroid, adoral zone not narrowed; 4-5 frontal cirri; 2-5 spiral rows of ventral cirri; short peristomal area (easily distinguished from Stichotricha by peristome); not tube-dwelling (?) (How to know the protozoa, 1979). Species:

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640

Strongylidium californicum Kahl: Cell body elongate, cylindroid 250 μm long; 4-5 frontal cirri; 2-5 spiral rows of ventral cirri; short peristomal area; not tube dwelling (How to know the protozoa, 1979).