Subgenus 3. Raphidodrymus, Haeckel.
Definition.—Pores of the spherical shell irregular, of different size or form. Radial spines arising from all the nodal-points of the network.
18. Acanthosphæra capillaris, n. sp.
Shell thin walled, with irregular polygonal meshes, twelve to twenty times as broad as the bars; eight to ten on the radius. Radial spines bristle-shaped, arising from all the nodal-points of the network, about as long as the diameter of the largest meshes.
Dimensions.—Diameter of the shell 0.15 to 0.2, pores 0.012 to 0.02, bars 0.001; length of the spines 0.02.
Habitat.—Central Pacific, Stations 260 to 274, surface.
19. Acanthosphæra arctica, n. sp.
Shell thin walled, with irregular roundish, polygonally framed meshes, three to four times as broad as the bars. Radial spines arising from all the nodal-points of the network, pyramidal at the base; in the distal half bristle-shaped, as long as the radius.
Dimensions.—Diameter of the shell 0.12, pores 0.006 to 0.008, bars 0.002; length of the spines 0.07.
Habitat.—Arctic Ocean, Greenland (in the stomach of Periphylla hyacinthina).
20. Acanthosphæra antarctica, n. sp.
Shell thick walled, with irregular, roundish pores, about as broad as the bars. Radial spines arising from all nodal-points of the network, conical at the base, half as long as the radius.
Dimensions.—Diameter of the shell 0.15, pores and bars 0.005 to 0.008; length of the spines 0.04.
Habitat.—Antarctic Ocean, Station 157, depth 1950 fathoms.
Subgenus 4. Rhaphidosphæra, Haeckel, 1881, Prodromus, p. 450.
Definition.—Pores of the spherical shell irregular, of different size or form. Radial spines scattered at intervals, not at all the nodal-points.
21. Acanthosphæra echinoides, Haeckel.
Shell thin walled, with irregular polygonal or more roundish pores of very different size. Forty to fifty very large meshes, separated by rows of much smaller meshes. Radial spines forty to sixty, half as long as the shell radius, bristle-shaped, with conical bases.
