Genus: Body blunt at rear; kineties spiralled when body contracts (Illustrated Guide, 1985).
Species:
cell body 400-600 μm; macronucleus moniliform (Kudo, 1966).
600 μm long (without expansion or attenuation);
peristome 1/2 body length; macronucleus moniliform;
size and the length of the peristome separate this species from S. ambiguum
(1-3 mm long, peristome 2/3 the body length) (Carey, 1992).