Family: Test usually more or less compressed; pseudostome narrowly oval or slit-like.
Genus: Test more or less flask-shaped, with more or less neck (Illustrated Guide, 1985).
Argynnia dentistoma (Penard 1890) ?,
test 90 μm long, 65 μm wide, L/W=1.4, pseudostome 15 μm wide,
x 640, a small marsh pond at Iwakagami-gunseichi (gregarious flowering area of Scizocodon soldanelloides), near Nagori-ga-hara (bog), Sukawa highland, Kurikoma mountain, Ichinoseki city, Iwate Pref., Japan, June 24, 2007 by Y. Tsukii
94 μm; x 640