(Brady, 1879)
Spinose, trochospiral, with 4 subspherical chambers in last whorl, aperture umbilical. Usually 2-3 apertures on spiral side. Sutures rather deep. Adult specimens thick-walled because of additional calcite secreted when they migrate to deeper water.
Distribution: Usually present in low numbers in warm to temperate waters, but Bénier (1985) reported rather high concentrations from the eastern tropical Atlantic. Deep dwelling (at the base of the seasonal thermocline).