Shell subovate, smooth, with slight collar stricture. Length of the two joints = 3 : 9, breadth = 4 : 8. Cephalis large, hemispherical, free, with small circular pores. Thorax inflated, ovate, with nine strong curved ribs, which are connected by five transverse circular rings at equal distances. Forty-five rounded, squarish, large meshes between them, in five transverse and nine longitudinal rows. Mouth constricted, smooth, half as broad as the thorax.
Dimensions.—Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.08 broad.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
3. Sethamphora dodecapleura, n. sp.
Shell urceolate, smooth, with sharp collar stricture. Length of the two joints = 3 : 9, breadth = 5 : 9. Cephalis flat, cap-shaped, free, with twelve ribs, and very small pores between them. Thorax thick-walled, inflated, with subcylindrical cavity, and twelve prominent sharp ribs, alternating with twelve longitudinal rows of very small circular pores (eight pores in each row). Mouth constricted, half as broad as the thorax.
Dimensions.—Cephalis 0.03 long, 0.05 broad; thorax 0.09 long, 0.09 broad.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
4. Sethamphora mongolfieri, Haeckel.
Eucyrtidium mongolfieri, Ehrenberg, 1854, Mikrogeol., Taf. xxxiv. fig. 18; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 72, Taf. x. fig. 3.
Shell urceolate, smooth, with distinct collar stricture. Length of the two joints = 2 : 9, breadth = 3 : 7. Cephalis campanulate, with eighteen ribs and small pores. Thorax nearly ellipsoidal, with eighteen prominent ribs, and eighteen longitudinal rows of regular circular pores between them (eight pores in each row; therefore 144 pores altogether). Mouth constricted, only one-third as broad as the thorax.