Family & Genus: >100 μm; oblong, or triangulate in locomotion; dorsal surface wrinkled, or ridged (Illustrated Guide, 1985).
Genus: A flattened ovoid or oblong, with longitudinal surface folds and appearance of thickened 'pellicle'; hyaloplasm a crescent at anterior end with thin extensions toward posterior end along sides; uninucleate (Page, 1976).