Family: Test rigid, chitinoid, oval to flask-shaped, clear; pseudostome terminal (Illustrated Guide, 1985).
Genus: Test ovate, discoid in cross-section; pseudostome a terminal slit (Illustrated Guide, 1985).
H. papilio
4 clips
test 56 x 37 μm
Torinome
Kuriso
Tochigi, 1999
Hyalosphenia sp.
3 clips
Numabe
Yamagata
Yamagata, 1999
H. papilio
4 clips
Shirasaka
Shirakawa
Fukushima, 1999