1. Mazosphæra hippotis, n. sp. (Pl. [5], fig. 8).
Shell spherical, with circular pores of irregular size and distribution, scarcely half as broad as the bars; fifteen to twenty on the half meridian of the shell. Between them, irregularly distributed, a variable number (ten to fifteen) of short cylindrical radial tubules, about twice as long as broad, and half as long as the shell radius. Mouth of the tubuli obliquely truncated, having on one side a strong acute tooth.
Dimensions.—Diameter of the shell 0.11 to 0.12, of the pores 0.002 to 0.004, of the bridges 0.006 to 0.009; length of the tubuli 0.03, breadth of them 0.01 to 0.015.
Habitat.—North Pacific, Station 253, depth 3125 fathoms.
2. Mazosphæra lagotis, n. sp. (Pl. [5], fig. 9).
Shell spherical, with circular pores of irregular size and distribution, about as broad as the bars; twelve to sixteen on the half meridian. Between them, irregularly distributed, a variable number (eight to twelve) of long, cylindrical, curved tubules, three to six times as long as broad, and about as long as the shell radius; their external mouth lateral, obliquely truncated, ovate, having on one side a strong conical tooth.
Dimensions.—Diameter of the shell 0.1 to 0.12, of the pores 0.002 to 0.01; length of the tubuli 0.05 to 0.07.
Habitat.—Central Pacific, Station 266, depth 2750 fathoms.
3. Mazosphæra lævis, Ehrenberg.
Mazosphæra lævis, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 297, Taf. vii. fig. 7.