4. Stylosphæra clio, n. sp. (Pl. [16], fig. 7).
Radial proportion of the two shells = 2 : 1. Cortical shell thick walled, smooth; pores regular, circular, three times as broad as the bars; fourteen to sixteen on the half equator. Polar spines three-sided pyramidal, very robust, with thick prismatic edges, about as long as the axis of the cortical shell, one-third as broad at the base. (Sometimes, as in the figured specimen, one spine is greater than the other; this form may be called Sphærostylus clio.)
Dimensions.—Diameter of the outer shell 0.12, pores 0.01, bars 0.003; inner shell 0.06; length of the polar spines 0.08 to 0.12, basal breadth 0.03 to 0.04.
Habitat.—Pacific, central area; Station 272, depth 2600 fathoms.
5. Stylosphæra polyhymnia, n. sp.
Radial proportion of the two spheres = 3 : 1. Cortical shell very thin walled, smooth, with regular, circular pores, three times as broad as the bars; sixteen to twenty on the half equator. Polar spines cylindrical, pointed, once and a half to twice as long as the axis of the outer sphere, scarcely broader than one pore. The two spheres are connected only by the two opposite beams.
Dimensions.—Diameter of the outer shell 0.12 to 0.16, pores 0.006 to 0.009, bars 0.002 to 0.003; inner shell 0.04 to 0.05; length of the polar spines 0.18 to 0.22, breadth 0.01.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, surface.
6. Stylosphæra dixyphos, Haeckel.
Haliomma dixyphos, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 83; Mikrogeol., Taf. xxii. fig. 31.