Family:
Genus: Cell body slightly assymmetrical, prolate ellipsoidal or nearly cylindrical in shape; both ends rounded; horizontal (slightly slanted) depression present at anterior end; a single flagella emerging from the depression nearly vertically to longitudinal axis of the cell body; "pro-basal body" present (?); cell body covered by a layer of submicroscopic scales; chloroplast essentially cup-shaped, but deeply incised forming two lateral lobes; each lobe with a pyrenoid; stigma posterior or absent; nucleus at anterior half of the cell body; one or two contractile vacuoles apical; 1-7 trichocysts (up to 5 μm long) present at posterior, arranging longitudinally (Süßwasserflora von Mitteleuropa 9, Chlorophyta I, 1983).

M. opisthostigma 7 clips 26 x 9 μm Akigase p. Saitama, 1998