Genus: Test variable, chitinoid; binucleate (Illustrated Guide, 1985).
Group [Vulgaroides]:
Test hemispherical; height 1/2 ~ 4/5 diam.; lacks external shelf or rim.
Species: 70-120 μm diam.,
50-75 μm high;
test yellow, brwon to black with age; pseudostome round, invaginated;
dorsal surface dimpled (Illustrated Guide, 1985).
Arcella gibbosa Penard,
cell body μm long, μm wide, L/W=,
x 640, No. 4, Okahotto-Yatsu Museum (a biotope including rice field), Okahotto, Abiko city, Chiba Pref., Japan, February 17, 2008 by Y. Tsukii
31 μm
63 μm
94 μm; x 640
Images of collecting locality:
No. 4, Okahotto-Yatsu Museum (a biotope including rice field), Okahotto, Abiko city, Chiba Pref., Japan, February 17, 2008 by Y. Tsukii