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).
Species:
Argynnia dentistoma (Penard 1890) or Difflugia sp. ?,
test 110 μm long, 88 μm wide, L/W=1.3,
pseudostome 35 μm wide, P/W=,
x 640, Onnenai, Kushiro marsh, Kushiro city, Hokkaido, Japan, October 16, 2005 by Y. Tsukii
31 μm
63 μm
94 μm; x 640