Cyclopyxis eurystoma Deflandre, 1929
Diagnosis: Shell yellow or brown, circular, and hemispherical in lateral view; shell surface rough except for the apertural collar; aperture circular, central and bordered by a smooth band of organic cement; shell yellowish – brownish, hemispherical with a circular, slightly invaginated aperture (distinction between C. eurystoma and Phryganella acropodia!). As a rule, aperture in relation to the diameter of the shell greater than in P. acropodia.
Dimensions: Deflandre (1929): diameter 60-66 µm; depth of shell 49-52 µm; diameter of aperture 32-34 µm. Other workers: diameter of shell 69-80 µm; depth of shell 46-55 µm; diameter of aperture 34-46 µm.
Ecology: mosses, Sphagnum
C. eurystoma alta Jung, 1942. Differs from the typical form of a higher shell. The diameter of the shell is 37–40 µm, the height of the shell is 45–47 µm, the diameter of the mouth is 13–16 µm.
C. eurystoma sinuosa Decloitre, 1970. Differs from a typical shape in a concave mouth. The diameter of the test is 35 µm, the height of the test is 40-45 µm, the diameter of the mouth is 20 µm.
Cyclopyxis eurystoma var. stenostoma Decloitre, 1949
Dimensions: Shell diameter 64-70 µm; shell depth 50 µm; pseudostome diameter 10-12 µm; pseudostome invagination 16-20 µm.