Genus: Species: Test small, brown or rarely colourless, oviform, compressed; trasverse section lenticular; 28-58 μm long, 19-50 μm wide, pseudostome 6-16 μm wide (Cash, 1915).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: No.5, Shijuhachi-ike (marsh pond), Shiga highland, Yamanouchi town, Nagano Pref., Japan, October 9, 2006 by Y. Tsukii