Subgenus 3. Stylosphærissa, Haeckel.
Definition.—Pores of the cortical shell irregular, of different size or form; surface smooth or a little rough, without thorns or spines.
12. Stylosphæra nana, n. sp. (Pl. [16], figs. 12, 13).
Radial proportion of the two spheres = 2 : 1. Cortical shell thick walled, somewhat irregular, smooth, with irregular, roundish pores, one to three times as broad as the bars; eight to ten on the half equator. Polar spines three-sided pyramidal, scarcely as long as the axis of the outer sphere, and nearly as broad at the base as its radius. (A very variable and irregular form.)
Dimensions.—Diameter of the outer shell 0.07 to 0.09, pores 0.003 to 0.009, bars 0.003; inner shell 0.03 to 0.04; length of the polar spines 0.04 to 0.07, basal breadth 0.03.
Habitat.—North Pacific, Stations 241 to 253, surface.
13. Stylosphæra jugata, n. sp.
Radial proportion of the two shells = 2 : 1. Cortical shell thick walled, smooth, with irregular, roundish, double-contoured pores, confluent in groups of two to six. On the half equator six to nine groups and fifteen to twenty pores; bars between them of very variable breadth. Polar spines very strong, three-sided pyramidal, twice as long as the axis of the outer sphere, half as broad at the base as its radius. (Nearly allied to Lithatractus jugatus, Pl. [16], fig. 2, but differs in the truly spherical form of both shells and the double length of the polar spines.)
Dimensions.—Diameter of the outer shell 0.15, pores 0.005 to 0.02; inner shell 0.07; length of the polar spines 0.25 to 0.3, basal breadth 0.03.
Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.