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



9. Acanthosjyhara insignis, Haeckel. 



Heliosphwra insignis, E. Hertwig, 1879, Organismus der Radiol., p. 40, Taf. v. fig. 7. 



Shell thin walled, about ten time.s as broad as one mesh. Pores regular, hexagonal, ten to 

 twelve times as broad as the bars. Eadial spines about one hundred and twenty, arising from 

 certain nodal-points of the network, being as long as the diameter of the sphere, three-sided prismatic, 

 with three thin denticulated edges. 



Dimensions. — Diameter of the shell 0-2, pores 0-02, bars 0-002 ; length of the spines 0-18, 

 breadth O'OOS. 



Habitat. — Cosmopolitan ; Mediterranean (Messina), Atlantic (Stations 325, 347), Indian 

 (Ceylon), Pacific (Stations 270 to 274), surface. 



10. Acanthosphcera fortispina, n. sp. 



Shell thin walled, about six times as broad as one mesh. Pores subregular, hexagonal, with 

 thread-like bars; three to four on the radius. Eadial spines about twenty, three-sided pyramidal, 

 , as long as the diameter, and oue-third as broad at the base as one pore. 



Dimensions. — Diameter of the shell 0-06 to 0-09, pores O'Ol to 01)14, bars below O'OOl ; length 

 of the spines 0-07 to 0-08, basal breadth 0-03 to 0-04. 



Habitat. — North Pacific, Station 244, depth 2900 fathoms. 



11. Acanthosphcera mucronata, n. sp. (PI. 26, fig. 7). 



Shell thick walled, fifteen times as broad as one pore. Pores regular, circular, hexagonally 

 framed, funuel-shaped, three times as broad as the bars. Eadial spines twenty to thirty, dagger- 

 shaped or spindle-shaped, angular, twice as broad in the middle as one pore, about as long as the 

 radius. 



Dimensions. — Diameter of the shell Q-ll, pores 0-0075, bars 0-0025; length of the spines 0-06, 

 breadth 0015. 



Habitat. — Central Pacific, Station 271, depth 2425 fathoms. 



12. Acanthosphcera clavata, n. sp. (PL 26, fig. 8). 



Shell thick walled, ten to twelve times as broad as one mesh. Pores subregular, cu-cular, three 

 times as broad as the bars. Eadial spines twenty, club-shaped, angular, with prominent edges, 

 twice as broad at the distal end as one pore, about as long as the radius. 



Dimensions. — Diameter of the shell 0-11, pores 0-01, bars 0-003 ; length of the spines 0-06, 

 breadth 0-02. 



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



13. Acanthosphcera marginata, n. sp. 



Shell thick walled, twelve times as broad as one mesh. Pores regular, circular double-edged, 

 four times as broad as the bars. Eadial spines conical, fourteen in number, about as long as the 



