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



(very similar to Xiphostylus phasianus, PI. 13, fig. 9, but different in the equal size and similar 

 form of the two large polar spines). 



Dimensions. Diameter of the sphere 012, pores 0'015, bars 0'005 ; length of the polar spines 

 O'l to 0-2, basal breadth 0-02. 



Habitat. Indian Ocean, Cocos Islands, surface, Eabbe. 



5. Xiphosphoera hebe, n. sp. 



Pores regular, circular, three times as broad as the bars. On the half equator sixteen to 

 twenty pores. Shell thick walled ; surface smooth. Polar spines conical or nearly cylindrical, 

 about as long as the axis of the sphere, as broad at the base as two pores. 



Dimensions. Diameter of the sphere O'l to 013, pores G'006, bars 0'002 ; polar spines O'l to 

 015 long, O'Ol thick. 



Habitat. Pacific, central area, Stations 265 to 268, depths 2700 to 2900 fathoms. 



6. Xiphosphcera maxima, n. sp. 



Pores regular, circular, twice as broad as the bars, funnel-shaped. Twenty to thirty pores on the 

 half equator. Shell very thick walled ; surface smooth. Polar spines three-sided pyramidal, about 

 as long as the radius of the sphere, as broad at the base as two pores. 



Dimensions. Diameter of the sphere 0'22 to 0'35, pores O'OOS to O'Ol, bars O'OOS ; polar spines 

 01 to 015 long, 0'02 thick. 



Habitat. Equatorial Atlantic, Station 347, depth 2250 fathoms. 



7. Xiphosphcera euphrosyne, n. sp. 



Pores regular, circular, about as broad as the bars, double contoured. Eight to ten on the half 

 equator. Shell thin walled ; surface smooth. Polar spines conical, about as long as the radius of 

 the sphere, as broad at the base as one pore. 



Dimensions. Diameter of the sphere 012 to 015, pores and bars 0'02 ; polar spines 0'06 to 

 0'09 long, 0'02 thick. 



Habitat. South Atlantic, Station 323, depth 1900 fathoms. 



Subgenus 2. Xiphosphoerella, Haeekel. 



Definition. Pores of the spherical shell regular, of nearly equal size and form ; 

 surface thorny or spiny, covered with regularly distributed papillae or thorns (in addition 

 to the two large polar spines). 



8. Xiphosphcera pallas, n. sp. (PL 14, fig. 4). 



Pores regular, circular, separated by hexagonal elevated frames, the sharp crest of which is 

 elegantly denticulated ; in each corner of the hexagons (between three pores) is a short radial spine, 



