6. Stylosphæra dixyphos, Haeckel.
Radial proportion of the two spheres = 2 : 1. Cortical shell thin walled, smooth, with regular, circular pores, twice as broad as the bars; ten to twelve on the half equator. Polar spines about as long as the axis of the outer shell, three-sided pyramidal, at the base twice as broad as one pore. (The two spheres connected by four beams, two opposite in the main axis, two opposite in the equatorial axis.)
Dimensions.—Diameter of the outer shell 0.1, pores 0.01, bars 0.05; inner shell 0.05; length of the polar spines 0.08 to 0.1, basal breadth 0.02.
Habitat.—South Atlantic, Station 332, surface; fossil in Tertiary rocks of Sicily.
Subgenus 2. Stylosphærella, Haeckel.
Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; surface thorny or spiny.
7. Stylosphæra setosa, Ehrenberg, 1872.
Radial proportion of the two shells = 2 : 1. Cortical shell thin walled, spiny; pores regular, hexagonal, four times as broad as the bars. Six to eight pores on the half equator. Polar spines conical, thin, scarcely as long as the radius of the cortical shell.
Dimensions.—Diameter of the cortical shell 0.1, pores 0.002, bars 0.005; medullary shell 0.05; length of the polar spines 0.04, basal breadth 0.01.
Habitat.—Philippine Sea, depth 3300 fathoms, Ehrenberg; Station 206, depth 2100 fathoms.
8. Stylosphæra euterpe, n. sp.
Radial proportion of the two shells = 3 : 1. Cortical shell thin walled, spiny; pores regular, circular, with hexagonal frames, twice as broad as the bars; eight to ten on the half equator. Polar spines conical, as thick as one pore at the base, about as long as the axis of the cortical shell.
Dimensions.—Diameter of the cortical shell 0.12, pores 0.012, bars 0.006; medullary shell 0.04; length of the polar spines 0.1, basal breadth 0.012.
Habitat.—South Pacific, Station 302, depth 1450 fathoms.
9. Stylosphæra melpomene, n. sp. (Pl. 16, fig. 1).
Radial proportion of the two shells = 3 : 1. Cortical shell thin walled, spiny, with regular, circular pores, four times as broad as the bars; eight to ten on the half equator. Polar spines three-sided prismatic, pointed, as broad as one pore, only one-third as long as the axis of the sphere (the two shells connected by four thin beams, two opposite in the main axis, two in the equatorial axis).
