10. Heliosphæra polygonaria, n. sp.
Shell very thin walled, with thread-like bars and irregular, polygonal pores (having four to eight angles, commonly five to seven); eight to ten on the radius. Radial spines at all the nodal-points of the network, bristle-shaped; forty to sixty main spines, as long as the radius, twice as thick as the numerous by-spines, which are not larger than one mesh.
Dimensions.—Diameter of the shell 0.15 to 0.2, pores 0.012 to 0.02, bars 0.001; length of the main spines 0.08 to 0.1.
Habitat.—Central Pacific, Stations 266 to 272, surface.
11. Heliosphæra heteracantha, n. sp.
Shell thin walled, with irregular, polygonal pores, twice to four times as broad as the bars; six to eight on the radius. Twenty radial main spines, three-sided pyramidal, nearly as long as the diameter of the shell, as broad as a larger mesh; innumerable bristle-shaped by-spines variously distributed on the bars and at the nodal-points of the net; half as long as the radius.
Dimensions.—Diameter of the shell 0.12, pores 0.006 to 0.012, bars 0.003; length of the main spines 0.1, basal breadth 0.012.
Habitat.—Equatorial Atlantic, Station 347, surface.
12. Heliosphæra hyperionis, n. sp.
Shell thick walled. Pores irregular, roundish, with polygonal frames, three to six times as broad as the bars; twelve to fourteen on the radius. Thirty to forty main spines, angular, pyramidal, scarcely as long as the radius and twice as long as the numerous bristle-shaped by-spines.