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



26. Acanthosphcera angulata, n. sp. (PI. 26, fig. 4). 



Shell thin walled ; its pores irregular, roundish, with angular, double-edged margin, two to four 

 times as broad as the bars ; six to eight on the radius. Twenty to thirty radial spines pyramidal, 

 angular, with prominent edges, shorter than the radius, as broad at the base as one small mesh. 



Dimensions. Diameter of the shell 0'2, pores - 02 to 0'04, bars O'Ol ; length of the spines 

 0-06, basal breadth 0'02. 



Habitat. South Atlantic, Station 332, depth 2200 fathoms. 



27. Acanthosphcera conifera, n. sp. 



Shell thick walled, with irregular, roundish pores, twice to five times as broad as the bars ; ten to 

 twelve on the radius. Twenty radial spines conical, regularly disposed, half as long as the radius, 

 as broad at the base as one of the largest meshes. 



Dimensions. Diameter of the shell 0'2, pores O'OOS to 0'02, bars 0'004 ; length of the spines 

 0-05, basal breadth 0'02. 



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



28. Acanthosphcera maxima, n. sp. 



Shell thick walled, with irregular, roundish pores, twice to eight times as broad as the bars ; twelve 

 to twenty on the radius. Eadial spines very numerous (two to three hundred), short, conical, 

 scarcely as long as the diameter of the largest meshes, and one-third as broad. 



Dimensions. Diameter of the shell 0'3 to 0'4, pores O'OOS to 0'03, bars 0'004 ; length of the 

 radial spines 0'03, basal breadth O'Ol. 



Habitat. Tropical Atlantic, Station 348, depth 2450 fathoms. 



29. Acanthosphcera simplex, Haeckel. 



Rhaphidococcus simplex, Haeckel, Monogr. d. Eadiol., 1862, p. 366, figs. 5, 6. 



Cladococcus simplex, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 800. 



Shell thick walled, with irregular, roundish pores, three to six times as broad as the bars ; eight 

 to nine on the radius. Forty to sixty radial spines, about as long as the diameter of the shell, 

 three-sided prismatic, not straight, but more or less bent. 



Dimensions. Diameter of the shell 012, pores 0'005 to 0'012, bars 0'0015 to 0'02 ; length of 

 the spines 012, breadth O'OOS. 



Habitat. Mediterranean (Messina), surface, Haeckel. 



30. Acanthosphcera gibbosa, n. sp. 



Shell thin walled, rugged or tuberculate, covered by about twenty hill-shaped tubercles or pro- 

 tuberances with flat valleys between them. Network very delicate, with thread-like bars and 



