Subgenus 3. Hexacontosa, Haeckel.
Definition.—Pores of the cortical shell irregular, of different size or form; surface smooth, without radial by-spines or papillæ (other than the six main spines).
16. Hexacontium axophænum, n. sp.
Cortical shell thin walled, smooth. Pores irregular polygonal, three to nine times as broad as the bars; seven to ten on the radius. Radial proportion of the three spheres = 1 : 3 : 8. Both medullary shells with smaller, irregular roundish pores. Six spines three-sided pyramidal, longer than the radius of the outer shell, one to two times as broad as one larger pore.
Dimensions.—Diameter of the outer shell 0.12, middle 0.045, inner 0.015; cortical pores 0.006 to 0.018, bars 0.002; length of the spines 0.06 to 0.12, basal breadth 0.02 to 0.03.
Habitat.—Central Pacific, Stations 266 to 272, at various depths.
17. Hexacontium polygonale, n. sp.
Cortical shell thick walled, smooth. Pores irregular roundish, with polygonal frames, two to four times as broad as the bars; eight to twelve on the radius. Radial proportion of the three spheres = 1 : 3 : 10. Six spines pyramidal, nearly as long as the diameter of the outer shell, with six to nine prominent edges (along the corner number of the polygonal meshes).
Dimensions.—Diameter of the outer shell 0.2, middle 0.06, inner 0.02; cortical pores 0.008 to 0.016, bars 0.004; length of the spines 0.16 to 0.18, basal breadth 0.02.
Habitat.—South Pacific, Station 295, depth 1500 fathoms.