Genus: Test variable, chitinoid; binucleate (Illustrated Guide, 1985).
Group [Vulgaroides]: Test hemispherical; height 1/2 ~ 4/5 diam.; lacks external shelf or rim.
Species: Test 30-100 μm in diameter; height of test about 1/2 the diameter; dome of hemispherical test evenly convex; pseudostome cicular, central; colorless, yellow, or brown; two vesicular nuclei; several contractile vacuoles (Kudo, 1966).
Test 100-150 μm in diameter, 50-80 high (Illustrated Guide, 1985).
Images of collecting locality:
No. 6, Mida-ga-hara (bog/marsh), Gassan (mountain), Tsuruoka city (formerly Haguro town) & Shonai town (formerly Tachikawa town), Yamagata Pref., Japan, August 3, 2006 by Y. Tsukii