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



Dimensions. — Diameter of the sphere O'l, jDores O'OOS to 0'015, bars O'OOS to O'OOS ; lengtli 

 of the major spine 0'15 to O'lS, of tlie minor 001 to 0'02, basal breadth 0'02. 

 Habitat. — Western Tropical Pacific, Station 225, depth 4475 fathoms. 



11. Xiphostylus falco, u. sp. (PI. 13, fig. 14). 



Pores irregular, roundish, two to five times as broad as the bars ; sixteen to eighteen on the half 

 equator. Surface smooth. Polar spines cylindrical, very stout, nearly half as thick as the radius 

 of the sliell ; major spine two to four times as long as the diameter of the shell ; minor spine 

 oliliquely inserted, scarcely longer than the diameter, divided at tlie end into two sliort, hook-sliaped, 

 curved branches. 



Dimensions. — Diameter of the spliere O'OS, jjores 0002 to 0'005, bars O'OOl ; breadth of the spines 

 0-02, length of the major spine 0-15 to 0-2, of the minor O'OO. 



Habitat. — South Pacific, Station 302, deptli 1450 fathoms. 



12. Xiphostylus alca, u. sji. (PL 14, fig. 13). 



Pores irregular, roundish, two to six times as broad as the bars ; six to eight on the half equator. 

 Each pore with three to six lobes, composed of tliree to six confluent smaller pores. Surface 

 smooth. Major spine conical, curved, somewhat longer than the axis of tlie spliere ; minor spine 

 somewhat shorter, pommel-like, edged. 



Dimensions. — Diameter of tlie sphere 0'07, pores O'Ol to 0'02, bars O'OOo ; lengtli of the major 

 spine 0'08, of the minor 0"06, basal thickness 0'02. 



Habitat. — Indian Ocean, Sunda Strait, Eabbe, surface. 



13. Xiphostylus edolius, n. sp. (PI. 13, fig. 5). 



Pores irregular, roundish, composed of two to six smaller confluent pores. On the half equator 

 six to eiglit large pores, and twenty to thirty small pores ; bars between the smaller very tliin. 

 Surface a little rougli. Major polar spine conical, S-shaped, about twice as long as the axis of the 

 shell ; minor spine pommel-shaped, edged, scarcely as long as its radius. 



Dimensions. — Diameter of tlie sphere 012, large pores O'Ol to 0-03, small jjores 0-004 to O'OOS, 

 bars 0001 to 0-004 ; length of the major spine 0-2, of the minor 0-05, basal breadth 0-02. 



Hetbitat. — Central Pacific, Station 273, surface. 



Subgenus 4. Xiphostylomma, Haeckel. 



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

 thorny or spiny. 



