Subgenus 2. Staurotholura, Haeckel.
Definition.—Surface of the shell with radial spines.
3. Staurotholus tetrastylus, n. sp. (Pl. [10], fig. 8).
The two principal cupolas smaller than the two lateral cupolas. Pores subregular, circular, three times as broad as the bars; six to eight in the semicircle of one cupola. Medullary shell elliptical. On the surface four long cylindrical radial spines; two in the principal and two in the lateral axis.
Dimensions.—Major axis of the cortical shell 0.15, minor 0.12; pores 0.012, bars 0.004.
Habitat.—South Pacific, Station 166, surface.
4. Staurotholus octostylus, n. sp.
The two lateral cupolas larger than the two principal cupolas. Pores subregular, circular, twice as broad as the bars; ten to twelve in the semicircle of one cupola. Medullary shell hexagonal, connected with each ring-like constriction by eight strong cylindrical radial spines (longer than the whole shell), lying in two crossed meridian planes, and corresponding to the eight diagonal wing-spines of Tetrapyle octacantha.
Dimensions.—Major axis of the cortical shell 0.12, minor 0.1; pores 0.008, bars 0.004.
Habitat.—Pacific, central area, Station 274, depth 2750 fathoms.