Tubuli conical, their outer opening half as broad as the inner and three times as broad as their height. Five to six pores on the quadrant. Diameter of the outer pores one and a half times as large as their distance from each other.
Dimensions.—Diameter of the shell 0.1, outer pores 0.01, their distance 0.007.
Habitat.—Mediterranean (Messina), surface, Haeckel.
2. Ethmosphæra conosiphonia, n. sp. (Pl. [12], figs. 5, 5a).
Tubuli conical, their outer opening two thirds as broad as the inner, and scarcely broader than their height. Ten to twelve pores on the quadrant. Diameter of the outer pores twice as large as their distance from each other.
Dimensions.—Diameter of the shell 0.17, outer pores 0.01, their distance 0.005.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms.
3. Ethmosphæra polysiphonia, n. sp. (Pl. [12], fig. 6).
Tubuli conical, their outer opening three-fourths as broad as the inner and three times as broad as their height. Sixteen to eighteen pores on the quadrant. Diameter of the outer pores three times as large as their distance apart.
Dimensions.—Diameter of the shell 0.2, outer pores 0.008, their distance 0.003.