Dimensions.—Diameter of the shell 0.11, pores 0.0075, bars 0.0025; length of the spines 0.06, breadth 0.015.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
12. Acanthosphæra clavata, n. sp. (Pl. [26], fig. 8).
Shell thick walled, ten to twelve times as broad as one mesh. Pores subregular, circular, three times as broad as the bars. Radial 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. Acanthosphæra 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. Radial spines conical, fourteen in number, about as long as the radius, and as broad at the base as one mesh. Six spines correspond to the six corners of a regular octahedron, eight to the centre of the eight faces.
Dimensions.—Diameter of the shell 0.1, pores 0.008, bars 0.002; radial spines 0.06, basal breadth 0.01.
Habitat.—Central Pacific, Station 274, surface.