Haeckel
Diagnosis: Inner shell mammillate, with 15 to 20 radial rods with numerous groups of 4 delicate, terminally dentate lateral spines. Outer shell with irregular pentagonal or hexagonal mesh openings, with numerous scattered forks of 2 or 3 delicate, divergent, terminally dentate spines, and with 20 to 30 larger simple radial spines, about half as long as the internal rods, distally with verticil of 3 to 5 slightly curved, simple, terminal branches.
Diameter: 1.0-2.2 mm.