Schmidt
Diagnosis: Thick-walled spherical shell, with nearly circular pores, slightly wider than bars, thick bars. Small mouth (about 3 times pore width), with 4 to 5 dagger-shaped teeth, about 4 to 5 times as long as pore width. Numerous by-spines, about 3 times as long as pore width.
Diameter: 0.9-1.0 mm.