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



8. Hexalonche grandis, n. sp. 



Cortical shell thick walled, smooth, four times as broad as the medullary shell. Pores of the 

 outer shell regtdar circular, four times as broad as the bars ; thirteen to fifteen on the radius. 

 Six spines conical, scarcely half as long as the radius, at the base as broad as one pore. 



Dimensio7is. — Diameter of the outer shell 0'2 to 0'32, pores O'Ol to 0'02, bars 0'003 to 0'005 ; 

 inner shell 0-06 to 0-08 ; length of the spines 0-06, breadth 0-02. 



Habitat. — Central Pacific, Station 268, depth 2900 fathoms. 



Subgenus 2. Hexalonchetta, Haeckel. 



Definition. — Pores of the cortical shell regular or subregular, of nearly equal size and 

 similar form ; surface covered witli numerous conical or bristle-shaped radial by-spines. 



9. Hexalonche amphisijyhon, n. sp. (PI. 25, figs. 2, 2a, 2h). 



Cortical shell thin walled, armed with very numerous bristle-shaped, radial by-spmes, a quarter 

 to a half as long as the six main spuies. Pores regular hexagonal, twelve to fourteen on the radius, 

 with very thin bars, prolonged on the outer as well as the inner surface iato a short truncated 

 conical tube (PI. 25, fig. 2b). Medullary shell octahedral, with irregular polygonal meshes and 

 very thin bars between them (fig. '2a), connected with the outer (six to eight times larger) shell 

 by six veiy thin radial beams. These are prolonged outside into six strong pyramidal spines, nearly 

 as long as the diameter of the outer shell, with sharp straight edges, at the base twice as broad 

 as one pore. 



Dimensions. — Diameter of the outer sheU 0-15, pores O'Ol, bars O'OOl ; inner shell 0'02 

 length of the spines 0"12, basal breadth 0'02. 



Habitat. — Central Pacific, Station 271, surface. 



10. Hexalonche anaximandri, n. sp. (PL 22, fig. 5). 



Cortical shell tliin walled, covered with short conical spuies (smaller than the pores), three 

 times as broad as the medullary shell. Pores of the outer shell subregular hexagonal, four times 

 as broad as the bars ; five to seven on the racUus. Inner shell with regular hexagonal pores of 

 half the size, connected with the outer by six strong, three-sided prismatic beams, which are 

 prolonged outside into six very stout pyramidal spiaes, with three promLuent edges, longer than 

 the radius and twice as broad as one pore. 



Dimensions. — Diameter of the outer shell 0'12, jjores O'Ol, bars 0'0025 ; inner shell O'O-i; 

 length of the spines 0'07, basal breadth 0'02. 



Habitat. — Central Pacific, Station 272, depth 2600 fathoms. 



