Argynnia vitrea (Penard, 1899)
Basionym: Nebela vitrea Penard, 1899

Diagnosis: Shell large, oval, sometimes slightly bumpy, narrowed toward the aperture, laterally compressed, very transparent and hyaline, occasionally with a faint lemon‑yellow tint. Test composed of flat, amorphous, thin scales that touch only loosely at their edges and are reinforced internally by smaller plates attached at the junctions of the larger scales. Aperture terminal, rather narrow, elliptical, and appearing finely toothed due to the bordering scales. Fundus of the shell broad and rounded.

Dimensions: Length 170–200 µm.

Ecology: Freshwater.