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 0.008 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. Acanthosphæra 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. Radial 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 0.008 to 0.03, bars 0.004; length of the radial spines 0.03, basal breadth 0.01.
Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.
29. Acanthosphæra simplex, Haeckel.
Rhaphidococcus simplex, Haeckel, Monogr. d. Radiol., 1862, p. 366, figs. 5, 6.Taf. xiii.
Cladococcus simplex, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 800.