Dimensions.—Diameter of the shell 0.13, larger pores 0.03, smaller 0.003; length of the spines 0.03.
Habitat.—Mediterranean (Nice), surface.
22. Acanthosphæra longispina, n. sp.
Shell thin walled, with irregular polygonal meshes, four to six times as broad as the bars; six to eight on the radius. Thirty to forty radial spines, three-sided prismatic, twice as broad as the bars, twice to three times as long as the diameter of the shell.
Dimensions.—Diameter of the shell 0.12 to 0.15, pores 0.012 to 0.02, bars 0.003; length of the radial spines 0.2 to 0.4, breadth 0.006.
Habitat.—North Pacific, Station 253, surface.
23. Acanthosphæra brevispina, n. sp.
Shell thick walled, with irregular polygonal meshes, twice to four times as broad as the bars; twelve to sixteen on the radius. Sixty to eighty radial spines, pyramidal, half as long as the radius of the shell, one-fourth as broad at the base.
Dimensions.—Diameter of the shell 0.2 to 0.22, pores 0.006 to 0.012, bars 0.003; length of the spines 0.05, basal breadth 0.02.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
24. Acanthosphæra acanthica, Haeckel.
Shell thick walled, with irregular, roundish pores, twice to three times as broad as the bars; seven to nine on the radius. Ten to twenty radial spines pyramidal, shorter than the radius, twice as broad at the base as one mesh.
Dimensions.—Diameter of the shell 0.12 to 0.16, pores 0.006 to 0.009, bars 0.003; length of the spines 0.04 to 0.06, basal breadth 0.01 to 0.015.
Habitat.—Fossil in Tertiary rocks of Sicily and Barbados.
25. Acanthosphæra haliphormis, Ehrenberg.
Shell thick walled, with irregular, roundish pores, twice to four times as broad as the bars; four to five on the radius. Twelve to twenty radial spines pyramidal, longer than the radius, scarcely as broad as one mesh at the base.
Dimensions.—Diameter of the shell 0.11, pores 0.01 to 0.02, bars 0.005; length of the spines 0.06 to 0.08, basal breadth 0.01.
Habitat.—Arctic Ocean, near Greenland, depth 1000 fathoms.
