Vannella simplex (Wohlfarth-Bottermann, 1960) Bovee, 1965
Diagnosis: Locomotive form semicircular or fan-shaped, often with long €˜tail€™. Frontal hyaloplasm occupies about half of the cell; the front edge may be smooth or slightly wavy. Rapidly moving cells often have a long €˜tail€™; in cultures and moist-chamber-preparations amoebae are commonly covered with patches of faecal pellets. Locomotive forms vary in size. Rounded vesicular nucleus 6€”11mm in diameter with single spherical central nucleolus. Floating form of radial type, with a number of fine, tapering hyaline pseudopodia.
Ultrastructure: Cell surface is covered with glycostyles about 100 nm in length; simple, filaments present among them.
Dimensions: Locomotive forms 25€”80 µm in greatest dimension (average 42€”52 µm). Nucleus 6€”11 µm in diameter.
Ecology: Freshwater, in different water types. Common in moist-chamber-slides where it multiplies easily.