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).
Dimensions.—Diameter of the outer shell 0.12, pores 0.012, bars 0.003; inner shell 0.04; length of the polar spines 0.04, thickness 0.013.
Habitat.—Indian Ocean, Cocos Islands, Rabbe.
10. Stylosphæra hispida, Ehrenberg, 1854.