Genus: Test ovate, discoid in cross-section; pseudostome a terminal slit (Illustrated Guide, 1985). Species: Test chitinous, transparent, yellowish; frontal view oblong-oval or pyriform, 110-140 μm long; a minute pore present on each side at the broadest point; lateral view elongate-pyriform; pseudostome forming a shallow notch; transverse section narrowly elliptic; (Cash, The British Freshwater Rhizopoda and Heliozoa vol. II, 1909).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.3, Yahei-daira (marsh), West of Higashidaiten, Azuma mountains, Yonezawa city, Yamagata Pref., Japan, July 1, 2007 by Y. Tsukii