Subgenus 1. Staurotholissa, Haeckel.
Definition.—Surface of the shell smooth or rough, without radial spines.
1. Staurotholus quadratus, n. sp.
Surface of the cortical shell smooth. All four cupolas nearly of the same size and form; therefore principal and lateral axes equal. Pores regular, circular, with hexagonal frames, twice as broad as the bars; eight to ten on the basal semicircle of one cupola. Medullary shell square.
Dimensions.—Diameter of the cortical shell 0.15; pores 0.01, bars 0.005.
Habitat.—South Atlantic, Station 323, depth 1900 fathoms.
2. Staurotholus cruciatus, n. sp.
Surface of the cortical shell rough. The two principal cupolas somewhat larger than the two lateral cupolas; therefore the longitudinal axis longer than the transverse. Pores irregular, roundish, twice to three times as broad as the bars; twelve to sixteen in the semicircle of one cupola.
Dimensions.—Major axis of the shell 0.16, minor 0.13; pores 0.005 to 0.009, bars 0.003.
Habitat.—Pacific, central area, Station 266, depth 2750 fathoms.