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



sutural pore, each of the twenty larger a couple of aspinal pores ; the elliptical aspiiial pores are 

 twice as broad as the circular sutural pores. The crests between the dimples are armed with simple 

 scattered short by-spines ; usually in the nodal points, where three combs meet, there exist 

 three or two diyergent by-spines. Tlie twenty radial main-spines are thin and long, compressed. 



Dimensions. — Diameter of the shell 0"22, of the aspinal pores 0'02, of the sutural pores O^Ol. 



Habitat. — Central Pacific, Station 271, surface. 



5. Ilystrichaspis armata, u. sp. 



Sliell with one hundred and seventy-six funnel-shaped dimples, one hundred and four of which 

 are blind and seventy-two perforated ; of the latter, each of the fifty-two smaller contains a single 

 sutural pore, each of the twenty larger a couple of aspinal pores. Crests between the dimples 

 comb-like, armed with a series of simple by-spines. Twenty main-spines very stout, in the inner 

 part cylindrical, in the outer shorter part conical. 



Dimomons. — Diameter of the shell 0'25, of the aspinal poi-es 0'02, of the sutural pores fl-Ol. 



Habitat. — South-East I'acific, Station 300, surface. 



6. Hi/strichasjyis sulcata, n. sp. 



Shell with one hundred and eighty-two funnel-shaped dimples, one hundred and eight of which 

 are blind and seventy-four perforated ; of the latter, each of the fifty-four smaller contains a 

 single sutural pore, each of the twenty larger a couple of aspinal pores. All pores nearly of the 

 same size, very small. Crests between tlie dimples very high, sulcated, on the free edge serrate 

 with short very numerous, simple by-spines. Eadial main-spines very, stout and short, conical. 



Dimensions. — Diameter of the shell 0'2, of the pores 0"003. 



Habitat. — South Atlantic, Station 325, surface. 



7. Hijstrichaspis foveolata, n. sp. 



Sliell with very numerous (three hundred to four hundreil ?) small and deep funnel-shaped 

 dimples, the majority of which are blind, the minority perforated ; among the latter there are forty 

 larger aspinal pores ; the other smaller (scarcely half as large) pores are sutural. Crests between 

 the dimples densely armed with simple short by-spines. Eadial main-spines stout, leaf-shaped. 



Dimensions. — Diameter of the shell 0'12, of the a.spinal pores O'Ol, of the sutural pores 0"004. 



Habitat. — Tropical Atlantic, Station 338, surface. 



8. Ilystrichaspis divaricata, n. sp. 



Shell with numerous (two hundred to three hundred ?) funnel-shaped dimples, the majority of 

 which are blind, the minority perforated ; among the latter there are forty larger aspinal pores. 



