18. Cenosphæra nirwana, n. sp.
Shell thick walled, smooth. Pores regular, circular, twice as broad as the bars, twenty-four to twenty-five on the quadrant.
Dimensions.—Diameter of the shell 0.25, pores 0.004, bars 0.002.
Habitat.—Indian Ocean, Belligemma, Ceylon, surface; Haeckel.
19. Cenosphæra maxima, n. sp.
Shell thick walled, smooth. Pores regular, circular, twice as broad as the bars, thirty to thirty-three on the quadrant.
Dimensions.—Diameter of the shell 0.3 to 0.4, pores 0.012, bars 0.006.
Habitat.—West Tropical Pacific, Station 225, depth 4475; also fossil in Barbados.
20. Cenosphæra compacta, n. sp. (Pl. 12, fig. 7).
Shell very thick walled, rough (its wall one-fourth to one-third as thick as the radius). Pores subregular, circular, of the same breadth as the bars, seven to eight on the quadrant.
Dimensions.—Diameter of the shell 0.15, pores and bars 0.012.
Habitat.—Central Pacific, Station 265, depth 2900 fathoms.
Cenosphæra radiata, Zittel, 1876 (L. N. 29, p. 84, Taf. ii. figs. 7, 8), a fossil Cretaceous species, is closely allied to Cenosphæra compacta.
21. Cenosphæra crassa, n. sp.
Shell very thick walled, rough (its wall nearly half as thick as the radius). Pores tubular, double-edged, regular, circular, ten times as broad as the thin united bars, twelve to fourteen on the quadrant.
Dimensions.—Diameter of the shell 0.14, pores 0.01, bars 0.001.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
22. Cenosphæra solida, n. sp.
Shell very thick walled, covered with innumerable short bristles (its wall one-third as thick as the radius). Pores regular, circular, four times as broad as the bars, tubular, eight to ten on the quadrant.
Dimensions.—Diameter of the shell 0.2, pores 0.02, bars 0.005.
Habitat.—Antarctic Ocean, Station 157, depth 1950 fathoms.
Subgenus 3. Cyrtidosphæra, Haeckel, 1862, Monogr. d. Radiol., p. 348.
Definition.—Pores of the spherical shell irregularly polygonal, of unequal size or form, sometimes roundish with polygonal frames.
