Three concentric latticed shells; surface of outermost usually thorny or spiny, pores medium-sized, regular or irregular in size and distribution, with or without polygonal frames. Usually 6 main spines opposite in pairs in three dimensive axes perpendicular to one another. Outermost shell diameter without spines: 70-100 µm. Poorly defined morphotype, probably includes several related species.
Ref.: Boltovskoy and Riedel (1980).