Haeckel
Diagnosis: Shell spheroidal with fairly regular triangular mesh openings. Radial tubes about 2 times as long as tangential bars, distal third very thin and with 8 to 12 whorls of 4 lateral branches, forked near the base to appear as 8 branches.
Diameter: 1.5-2.0 mm in equatorial samples; 2.5-3.0 mm in Antarctic samples.