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.
Cenosphæra acanthica, Stöhr, 1880, Palæontogr., vol. xxvi. p. 86, Taf. i. fig. 3.
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.