Diagnosis: Shell ovoid, rigid, in diameter circular or slightly compressed, organic, densely agglutinated with small mineral particles; aperture small, irregular shaped, flexible and variable in shape and size; nucleus hard to detect, because of the dense covering with xenosomes. Filopodia long, branching and anatomizing, with small veils. Living cells collect a bunch of debris around their pseudostome.
Dimensions: Length c. 64-79 µm, breadth 28-40 µm, aperture c. 3.6-6.7 µm.
Ecology: shallow freshwater pond, Crailoo, The Netherlands. Cells easily multiplied in wet mounts when kept in humidity chambers.
Remarks: Though the shell is ovoid, it occasionally bears a tuft of debris on its fundus, giving it the appearance of a pointed shell (see image below).