Heleopera sylvatica Penard, 1890
Diagnosis: Shell slightly yellowish, transparent, obovoid, flattened about 2:1, composed of siliceous shell platelets from other testaceans and sometimes rough xenosomes, found mainly in aboral region. Some individuals are completely covered with such acquired idiosomes. The aboral region often has euglyphid platelets (Euglypha, Trlnema) extending at right-angles like spines. Aperture terminal, slightly convex in broad view, slit-like to elliptic with small border of organic cement. Nucleus with several nucleoli.
Dimensions: Penard (1890): 50-75 µm, Lueftenegger and Foisner (1991): 59-70 µm; my measurements: 66-69 µm.
Remarks: I found these specimens in a sample from mosses on a rock in a wood near Saarburg, Germany.