Family: Pseudostome terminal; plate rectangular, siliceous or calcareous (Illustrated Guide, 1985).
Genus: (Illustrated Guide, 1985).
->> Description at WPRNO Google Image Search
Similar genus -- >> Quadrulella;
M. musciphila ?
or Paraquadrula ?
37 x 25 μm
Riverside green l.
Sawara
Chiba, 2004