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



Dimensions. — Diameter of the outer sphere 0-12, pores 0-014, bars O'OO? ; inner sphere Q-OG ; 

 lengtli of the major spine OlS, of the minor 0-05, greatest breadth 0-04 

 Habitat.- — Southern Pacific, surface. Station 289. 



Subgenus 3. SphcBrostylissa, Haeckel. 



Definition. — Pores of the cortical shell irregular, of diflerent size or form ; surface 

 smooth or a little rough. 



6. SphoBTOstylus cottus, n. sp. 



Cortical shell thick walled, smooth, about twice as broad as the medullary shell, with iiTegular, 

 roundish pores, scarcely larger than the bars ; fifteen to twenty on the half equator. Polar spines 

 conical, the major once and a half to twice as long as the axis of the outer sphere, the minor 

 scarcely as long as its radius. 



Dimensions. — Diameter of the outer sphere 0'14, pores and bars O'OOS to 0-012 ; inner sphere 

 0'065 ; length of the major spine 0'2 to 0'3, of the minor 0'05 to 0'07, basal breadth 0'G3. 



Habitat. — Northern Atlantic, Faeroe Channel, surface, John Murray. 



7. SphcBrostyliis trigia, u. sp. 



Cortical shell thin walled, smooth, three times as bix)ad as the medullary shell, with in-egular, 

 roundish jjores, two to three times as broad as the bars ; ten to twelve on the half equator. Polar 

 spines very unequal ; the major three-sided pyramidal, one and a half times as long as the axis 

 of the outer sphere ; the minor scarcely as long as its radius, edged, pommel-like. 



Dimensions. — Diameter of the outer sphere 012, pores O'Ol to 0-015, bars 0'005 ; inner sphere 

 0'04 ; length of the major spine 0'2, of the minor 0'05, breadth O^OS. 



Habitat. — Northern Pacific, Station 241, depth 2300 fathoms. 



Subgemis 4. Sphcerostylomma, Haeckel. 



Definition. — Pores of the cortical shell ii-regular, of difiereut size or form ; surface 

 spiny or thorny. 



8. Splice rostylus ophidium, n. sp. (PI. 16, figs. 14, 15). 



Stylosphaira opliidium, Haeckel, 1878, Atlas, Juc. cit. 



Cortical shell thin walled, thorny, twice as broad as the medidlaiy shell, with irregidar, roundish 

 pores ; eight to ten on the half equator. Polar spines conical, more or less curved or S-shaped ; the 

 minor scarcely as long as the axis of the outer sphere, the major two to three times as long. 



