Genus: Test round in cross-section; scales usually adjacent; aperture truncate (Illustrated Guide, 1985).
Cyphoderia compressa Golemansky ? (outline shape similar to C. ampulla but shapes of scales are different) ,
test 115 μm long, 38 μm wide, L/W=3.0,
pseudostome 16 μm wide,
x 640, Furuike marsh, Togakushi highland, Shinano town, Nagano Pref., Japan, June 12, 2005 by Y. Tsukii
94 μm; x 640