Genus: Test variable, chitinoid; binucleate (Illustrated Guide, 1985).
Species:
Arcella catinus or (Arcella arenaria ?),
test 113 μm long, 104 μm wide, pseudostome nearly circular, 32 μm wide,
x 640, a small wetland near Numa-no-hara marsh (Genseikaen), Madarao highland (Niigata & Nagano Pref.), Myoko village, Niigata Pref., Japan, May 15, 2005 by Y. Tsukii
31 μm
63 μm
94 μm; x 640