BIORBIS Strank, 1983
Type species: Biorbis duplex Strank, 1983; OD.
Biorbis Strank, 1983 (*3075), p. 441.
Test consisting of two concentric spheres or ellipsoids, the outer being up to 0.35 mm in diameter; wall calcareous, microgranular to granular, outer sphere with wall of up to 0.05 mm thickness, wall of each sphere differentiated into a dark microgranular outer layer that grades inward into a less dense and more granular region and then into a second dark and dense microgranular inner layer, no perforations observed; no aperture known. L. Carboniferous (Dinantian); England.