Genus: Cytostome in rear 1/3 of body (Illustrated Guide, 1985). Irregular, almost triangular in shape; anterior pointed; posterior rounded; distinctly flattened with a delicate keeled armour; somatic ciliation reduced; ventrally 3 longitudinal cilary rows; cytostome in a depression at posterior ventral region; tooth-like projection on the left side (Carey, 1992).
Species:

M. simulans Kahl: 30-35 μm long (Kudo, 1966). Body laterally compressed; 30-35 μm long; several ridges on left side; 3 rows of cilia & cytostome on right side; cytostome post-central; with curved ectoplasmic lip bearing a small undulating membrane on the inner side; two contractile vacuoles (How to know the protozoa, 1979).

M. sulcatus Englemann, 1862: 30-40 μm long; a single macronucleus; two contractile vacuoles (Carey, 1992).