Placocista lens (Penard, 1899)
Diagnosis: shell broad, ovoid, strongly compressed, with acute lateral border; shell edge smooth, without spines; shell composed of many small scales; along the aperture is an area covered with very minute scales; aperture a broad but very flattened slit, biconvex; nucleus spherical, with fragmented nucleolar material; filopodia.
Dimensions: Length 81 µm, L/B = 0.8, scales ca. 12 µm.
Ecology: Rare. I have found one specimen in 1979 in a sample from the Dammerkade, Ankeveen, one in 2011 in a sample from a small river in Neer, Zuid-Limburg, and one in the Laegieskamp (2013), all in the Netherlands.
Remarks: This species has never been recorded by Hoogenraad & De Groot (1940) for the Netherlands.