Plagiopyxis intermedia  Bonnet, 1959

Diagnosis: Shell clear, transparent, circular or slightly elliptical in dorsal view. In lateral view, the ventral side presents a rather marked declivity and ends in a shell much less clear than in Plagiopyxis penardi Thomas. Net pseudostome, in narrow fissure; fairly weak cryptostomy. The dorso-posterior part of the test always presents a covering of dark-brown to black colored particles (fungal origin?) mixed with normal siliceous elements.

Dimensions: Shell diameter 50 to 60 µm; dorso-ventral (height) 28 to 32 µm.

Ecology: This extremely ubiquitous species is found in many aerophilic environments (rhizospheres of rupicolous plants on all rocks, and mosses in the same conditions). It is particularly abundant in the Pyrénées-Orientales.

Remarks: Plagiopyxis intermedia differs: 1) from Plagiopyxis declivis by its smaller dimensions, its slightly cupped ventral lip and its constant dark particles; 2) of Plagiopyxis minuta by its larger dimensions and its sloping ventral side.