Haecker
Diagnosis: Thick-walled spherical shell, with small circular pores about 1-2 times bar width. Mouth relatively small, with a ring of teeth and 1-3 main-spines, of which one is sculptured in a net-like pattern. Thick main-spines, length about half the shell radius. Numerous by-spines, about 3 times pore width.
Diameter: 0.8-1.0 mm.