Cortical shell thin walled, smooth, three times as broad as the medullary shell, with irregular, roundish pores, two to three times as broad as the bars; ten to twelve on the half equator. Polar spines very unequal; the major three-sided pyramidal, one and a half times as long as the axis of the outer sphere; the minor scarcely as long as its radius, edged, pommel-like.
Dimensions.—Diameter of the outer sphere 0.12, pores 0.01 to 0.015, bars 0.005; inner sphere 0.04; length of the major spine 0.2, of the minor 0.05, breadth 0.03.
Habitat.—Northern Pacific, Station 241, depth 2300 fathoms.
Subgenus 4. Sphærostylomma, Haeckel.
Definition.—Pores of the cortical shell irregular, of different size or form; surface spiny or thorny.
8. Sphærostylus ophidium, n. sp. (Pl. [16], figs. 14, 15).
Stylosphæra ophidium, Haeckel, 1878, Atlas, loc. cit.
Cortical shell thin walled, thorny, twice as broad as the medullary shell, with irregular, roundish pores; eight to ten on the half equator. Polar spines conical, more or less curved or S-shaped; the minor scarcely as long as the axis of the outer sphere, the major two to three times as long.
Dimensions.—Diameter of the outer sphere 0.11, pores 0.01 to 0.017, bars 0.003 to 0.007; diameter of the inner sphere 0.06, pores 0.005 to 0.008, bars 0.002 to 0.004; length of the major polar spine 0.25, of the minor 0.1, basal breadth 0.03.
Habitat.—Indian Ocean, Madagascar, Rabbe, surface.