Dimensions.—Diameter of the outer shell 0.13, middle 0.04, inner 0.02; cortical pores and bars 0.008; length of the spines 0.04, basal breadth 0.02.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
5. Hexacontium triplosphærium, n. sp.
Cortical shell thick walled, smooth. Pores regular circular, three times as broad as the bars; ten to twelve on the radius. Radial proportion of the three spheres = 1 : 3 : 10. Six spines conical, about as long as the radius of the cortical shell.
Dimensions.—Diameter of the outer shell 0.16, middle 0.05, inner 0.016; cortical pores 0.012, bars 0.004; length of the spines 0.07, basal breadth 0.02.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
6. Hexacontium octahedrum, n. sp.
Cortical shell a regular octahedron, thin walled, with twelve more or less rounded edges (between the spine-bases) and with smooth surface; its pores regular circular, five to seven on the radius, four times as broad as the bars. Radial proportion of the three shells = 1 : 3 : 9. Both medullary shells spherical, with very small circular pores. Six inner bars very thin; six outer spines (their prolongations) triangular pyramidal, as long as the radius of the outer shell. (Differs from Hexalonche octahedra, Pl. [22], fig. 8, almost solely in the duplication of the medullary shell.)
Dimensions.—Diameter of the outer shell 0.12, middle 0.04, inner 0.013.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.