Genus (Deflandre, 1928): Test round or oval in cross-section;
pseudostome with clear crenulate rim (Illustrated Guide, 1985).
Species: 25-60 μm long; 15-40 μm diam.; test clear, elliptical, round cross-section; with round, overlapping scales; no spines; pseudostome terminal, 8-12 μm; on short, dentate collar (Illustrated Guide, 1985).
Images of collecting locality:
Maimeno-ike (pond), Norikura highland, Azumi, Matsumoto city (formerly Azumi village), Nagano Pref., Japan, June 8, 2006 by Y. Tsukii