9. Acanthosphæra insignis, Haeckel.
Shell thin walled, about ten times as broad as one mesh. Pores regular, hexagonal, ten to twelve times as broad as the bars. Radial 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 0.003.
Habitat.—Cosmopolitan; Mediterranean (Messina), Atlantic (Stations 325, 347), Indian (Ceylon), Pacific (Stations 270 to 274), surface.
10. Acanthosphæra 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. Radial spines about twenty, three-sided pyramidal, as long as the diameter, and one-third as broad at the base as one pore.
Dimensions.—Diameter of the shell 0.06 to 0.09, pores 0.01 to 0.014, bars below 0.001; 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. Acanthosphæra mucronata, n. sp. (Pl. 26, fig. 7).
Shell thick walled, fifteen times as broad as one pore. Pores regular, circular, hexagonally framed, funnel-shaped, three times as broad as the bars. Radial 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 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
