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



12. Xiphosphcera ceres, n. sp. 



Pores irregular, roundish, of different sizes, two to four times as broad as the bars. Sixteen to 

 twenty pores on the half equator. Shell thin walled, with smooth surface. Polar spines conical, 

 about as long as the axis of the sphere, very thick at the base. 



Dimensions. Diameter of the sphere 015 to 0'2, pores 0'004 to O'OOS, bars 0'002 ; polar spines 

 018 to 0'24 long, at the base 0'02 thick. 



Habitat. North Atlantic, Station 353, surface. 



13. Xiphosphcera clavigera, n. sp. 



Pores irregular, roundish, double contoured, of very unequal size, two to seven times as broad as 

 the bars ; ten to twelve on the half equator. Shell thick walled ; surface a little rough. Polar spines 

 club-shaped, with prominent edges, about half as long as the axis of the sphere, thinner at both ends 

 than in the middle. (Differs from Ellipsoxiplius clamger, PI. 14, fig. 3, in the spherical shell and 

 shorter spines.) 



Dimensions. Diameter of the sphere 0'2, pores 0'005 to 0'02, bars 0'003 ; polar spines O'OG 

 long, 0'02 broad. 



Habitat. Pacific, central area, Station 274, depth 2750 fathoms. 



Subgenus 4. Xiphosphceromma, Haeckel. 



Definition. Pores of the spherical shell irregular, of different size or form ; surface 

 thorny or spiny (besides the two large polar spines). 



14. Xiphosphcera vesta, n. sp. (PL 14, fig. 6). 



Pores irregular, roundish, three to five times as broad as the bars ; fourteen to sixteen on the 

 half equator. Scattered on the surface of the thick-walled shell are from twenty to thirty strong 

 three-sided pyramidal spines of unequal size, the largest twice as long as the largest pores. Polar 

 spines very strong, nearly three-sided prismatic, with curved edges, nearly as long as the axis of 

 the sphere and twice as broad as the largest pores. 



Dimensions. Diameter of the sphere 017, pores O'Ol to 0'02, bars 0'004 ; length of the polar 

 spines 013, thickness 0'02 to 0'03. 



Habitat. Pacific, central area, Station 266, depth 2750 fathoms. 



15. Xiphosphcera astrcea, n. sp. 



Pores irregular, roundish, one to two times as broad as the bars ; ten to twelve on the half 

 equator. Surface of the thick-walled shell covered with numerous short conical thorns. Polar 

 spines cylindro-conical, one and a half to two times as long as the axis 'of the sphere. 



