Spongy framework of the sphere everywhere of the same structure, with almost equal meshes, ten to twelve times as broad as the bars. Sixteen to twenty radial main spines, longer than the shell diameter, three-sided prismatic, with three serrated edges, beginning about the middle of the radius and increasing in thickness to the truncated distal end. Between them occur numerous thin, bent, bristle-shaped by-spines. (Very similar to Spongosphæra helioides, Monogr. d. Radiol., Taf. xii. figs. 11-13, but without medullary shells.)
Dimensions.—Diameter of the sphere 0.3; length of the main spines 0.4, of the by-spines 0.01.
Habitat.—Tropical Atlantic, Station 352, surface.
6. Spongiomma multiaculeum, Haeckel.
Spongechinus multiaculeatus, Dunikowski, 1882, Denkschr. d. k. Akad. d. Wiss. Wien, Bd. xlv. p. 29, Taf. v. figs. 60-63.
Spongy framework of the sphere very compact, with small meshes, scarcely broader than the bars; four to eight large main spines, three-sided pyramidal, longer than the shell radius; numerous (thirty to forty) thin by-spines, scarcely half as long.
Dimensions.—Diameter of the sphere 0.16; length of the main spines 0.11, of the by-spines 0.03.
Habitat.—Fossil in the Alpine Jura, Schafberg near Salzburg (Dunikowski).
7. Spongiomma asteroides, n. sp.
Spongy framework in the central part of the sphere much denser and darker than in the peripheral part. Sixty to eighty cylindro-conical main spines, as long as the radius, between them are numerous straight, bristle-shaped by-spines half that length.