Genus Placocista Leidy, 1879

Diagnosis: shell ovoid, strongly compressed, with acute lateral border; shell edge with or without short, lanceolate spines; shell composed of many small scales; aperture a broad slit, biconvex with pointed edges; nucleus spherical; filopodia.

Two species were found in the Netherlands:

with spines: Placocista spinosa
without spines: Placocista lens