66 THE VOYAGE OF H.M.S. CHALLENGER. 



23. Cenosphcera reticulata, Haeckel. 



CyrtidospJuBra reticulata, Haeckel, 1862, Monogr. d. Eadiol., p. 349, Taf. xi. fig. 2. 



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 016, pores 0'004 to 0-016, bars 0'002. 



Habitat. Mediterranean (Messina), surface. 



24. Cenosphcera 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 sheU 0'25, pores 0'002 to O'OOS, bars under O'OOl. 

 Habited. Central Pacific, Station 271, surface. 



25. Cenosphcera 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 O'OOo. 

 Habitat. North Pacific, Station 236, surface. 



26. Cenosphcera papillata, n. sp. 



Shell thick walled, covered with short conical papillae. Pores irregular, polygonal, three to five 

 times as broad as the bars, fourteen to sixteen on the quadrant. 



Dimensions. Diameter of the shell 012, pores 0'004 to 0'007, bars O'OOIS. 

 Habitat. South Atlantic, Station 325, surface. 



27. Cenosphcera 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 016, pores 0'006 to O'Ol, bars 0'003. 

 Habitat. North Pacific, Station 254, surface. 



28. Cenosphcera perforata, n. sp. (PL 26, fig. 10). 



Ceriosphcera perforata, Haeckel, 1881, Prodromus et Atlas, loc. cit. 



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 



