Haecker
Diagnosis: Thin-walled shell basically spherical, with elevations at base of main-spines suggesting polyhedral shape, with small (4-6 times bar width) circular to subcircular or polygonal pores. Bars often rectangular in cross section, giving pores cylindrical shape, especially in smaller specimens. Mouth variable in size, usually with thin but distinct rim and 1-3 main-spines. Main-spines long (longer than diameter), elevated and fenestrated at base.
Diameter: 0.25-0.65 mm.