Pseudocorythion acutum (Wailes, 1927)
Diagnosis: Test small, colorless, elliptical, slightly flattened dorso-ventrally; fundus terminating in a short spine, aperture large, circular, everted, opening ventrally; test formed of circular or sub-circular plates, arranged more or less regularly in diagonal rows; animal not observed.
Dimensions: Length 50-55 µm; breadth about 23 µm; thickness 20 µm; aperture 16 µm in diameter; spine 5 µm in length; plates of test 3 µm in diameter and 1.5 µm in thickness.
Ecology: Marine. On the sea beach, Camp Island, British Columbia.
Remarks: Although found on the sea shore, it is in all probability a freshwater or moss inhabiting species.