Proportion of the major axis to the minor = 7 : 6. Shell thick walled, with subregular, circular meshes, five to six times as broad as the bars; ten to twelve on the half equator. Surface smooth. Polar spines sharp edged (six-sided?), very unequal; longer spine straight, about equal to the minor axis; shorter spine obliquely inserted, scarcely half as long, shaped like a bird's head.
Dimensions.—Longer axis 0.15, shorter axis 0.13; pores 0.02, bars 0.004; length of the polar spines—longer 0.1, shorter 0.05.
Habitat.—Central area of the Pacific, Station 272, depth 2600 fathoms.
5. Ellipsostylus columba, n. sp. (Pl. [13], fig. 3).
Proportion of the major axis to the minor = 4 : 3. Shell egg-shaped, thin walled, with regular, circular meshes, three times as broad as the bars; ten to twelve on the half equator. Surface somewhat thorny. Polar spines nearly of equal length (equal to the major axis), but of very different form; one straight, pyramidal, and obliquely inserted, the other like a bird's head.
Dimensions.—Longer axis 0.08, shorter 0.06; pores 0.003, bars 0.01; length of the spines 0.09.
Habitat.—South Atlantic, Station 332, surface.
6. Ellipsostylus ciconia, n. sp. (Pl. [13], fig. 8).
Proportion of the major axis to the minor = 7 : 5. Shell egg-shaped, thick walled; the meshes very small, regular, circular, three times as broad as the bars; sixteen to twenty on the half equator. Surface uneven. Polar spines nearly cylindrical, pointed; the smaller obliquely inserted, equal to the major axis; the larger more than twice as long and thick, furrowed at its base. (Compare with this and the allied species Rhabdolithis pipa, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. i. fig. 27.)
Dimensions.—Longer axis 0.07, shorter 0.05; pores 0.003, bars 0.001; length of the polar spines—longer 0.2, shorter 0.08.