23. Cenosphæra reticulata, Haeckel.
Shell very thin walled, smooth. Pores irregular, polygonal, two to eight times as broad as the bars, fifteen to twenty on the quadrant (groups of four to eight smaller meshes are scattered on the surface, and separated by reticular rows of larger meshes).
Dimensions.—Diameter of the shell 0.16, pores 0.004 to 0.016, bars 0.002.
Habitat.—Mediterranean (Messina), surface.
24. Cenosphæra tenerrima, n. sp.
Shell extremely thin walled, smooth, like a cobweb. Pores very irregular and small, polygonal with thread-like bars, thirty to forty on the quadrant.
Dimensions.—Diameter of the shell 0.25, pores 0.002 to 0.008, bars under 0.001.
Habitat.—Central Pacific, Station 271, surface.
25. Cenosphæra polygonalis, n. sp.
Shell thin walled, smooth, with irregular, polygonal pores, three to four times as broad as the bars, eight to ten on the quadrant.
Dimensions.—Diameter of the shell 0.2, pores 0.012 to 0.02, bars 0.005.
Habitat.—North Pacific, Station 236, surface.
26. Cenosphæra papillata, n. sp.
Shell thick walled, covered with short conical papillæ. Pores irregular, polygonal, three to five times as broad as the bars, fourteen to sixteen on the quadrant.
Dimensions.—Diameter of the shell 0.12, pores 0.004 to 0.007, bars 0.0015.
Habitat.—South Atlantic, Station 325, surface.
27. Cenosphæra cristata, n. sp.
Shell thick walled, rough. Pores irregular, roundish, surrounded by polygonal crested frames two to three times as broad as the bars, eight to twelve on the quadrant.
Dimensions.—Diameter of the shell 0.16, pores 0.006 to 0.01, bars 0.003.
Habitat.—North Pacific, Station 254, surface.
28. Cenosphæra perforata, n. sp. (Pl. 26, fig. 10).
Shell thick walled, rough. Pores irregular, roundish, surrounded by high polygonal funnel-shaped frames, which are solid in the inner half, perforated by numerous very small pores in the
