4. Arachnosphæra increscens, n. sp.
Innermost shell with regular, hexagonal meshes; its diameter three times as long as the distance between it and the second shell, quite as long as the distance between the fifth and sixth shells; the distances between the concentric shells gradually increasing from the centre. Radial spines about fifty to sixty, each with six to eight verticils.
Dimensions.—Diameter of the innermost shell (A) 0.75; distances between the following shells—A, B = 0.025, B, C = 0.037, C, D = 0.05, D, E = 0.062, E, F = 0.075, &c.
Habitat.—Central Pacific, Station 271, surface.
Subgenus 2. Arachnosphæromma, Haeckel.
Definition.—Pores of the innermost shell irregular, polygonal.
5. Arachnosphæra tenuissima, n. sp.
Innermost shell with irregular, polygonal meshes; its diameter twice as long as the equal distance between every two concentric shells. Forty to fifty radial spines, each with twelve to sixteen verticils.
Dimensions.—Diameter of the innermost shell 0.1, distance between the concentric shells 0.04 to 0.05.
Habitat.—South Atlantic, Station 332, surface.