Shell nut-shaped, tuberculate, with slight sagittal stricture and scattered small circular pores. Basal plate with four large collar pores (sometimes surrounded by several small peripheral pores). Apical horn slender, conical, as long as the shell. Feet sixteen to twenty, laminated and truncate, of the same length, nearly vertical and parallel. _Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.05 to 0.07 long. _Habitat._--Fossil in Barbados. {1062}8. _Petalospyris anthemis_, n. sp. Shell nut-shaped, spinulate, with deep sagittal stricture and irregular, roundish pores. Basal plate with four large pores of equal size. Apical horn conical, twice as long as the shell. Feet twenty to thirty, laminated and truncate, as long as the shell, divergent. _Dimensions._--Shell 0.05 long, 0.08 broad; horn 0.1 long, feet 0.6 long. _Habitat._--Central Pacific, Station 272, depth 2600 fathoms. 9. _Petalospyris tessaromma_, n. sp. Shell subspherical, with slight sagittal stricture and few small pores; on each side of the stricture four larger, square, annular pores. Basal plate with four large collar pores (two larger cardinal and two smaller jugular pores). Horn and feet conical, about half as long as the shell. Feet twenty to twenty-five, slightly curved, convergent. _Dimensions._--Shell diameter 0.08; horn and feet 0.04. _Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil in Barbados. Subgenus 4. _Petalospyromma_, Haeckel. _Definition._--Basal plate with numerous (six or more) collar pores, commonly three or four larger central, and six to twelve smaller peripheral pores. 10. _Petalospyris novena_, n. sp. (Pl. 83, fig. 12). Shell nut-shaped, tuberculate, with slight sagittal stricture and irregular, roundish pores. Basal plate with nine pores (three large primary and three alternate pairs of small secondary pores). Nine long corresponding feet, twice to four times as long as the shell (three very thick primary, and three alternate pairs of thin secondary feet). All feet cylindrical, curved, widely divergent. Horn conical. _Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.15 to 0.25. _Habitat._--Indian Ocean (Cocos Islands), Rabbe, surface. 11. _Petalospyris argiscus_, Ehrenberg. _Petalospyris argiscus_, Ehrenberg, 1875, Abhandl. d. k. Akad. Wiss. Berlin, p. 80, Taf. xxii. figs. 1, 2. _Petalospyris argiscus_, Bütschli, 1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. 539, Taf. xxxii. fig. 17, _a_, _b_. Shell nut-shaped, tuberculate, with slight sagittal stricture and irregular, roundish pores. Basal plate with nine pores (three larger central and three alternate pairs of smaller peripheral pores). {1063}Apical horn slender, spindle-shaped, about as long as the shell. Twenty to twenty-five feet, of the same length, broad, lamellar and truncate, nearly vertical, slightly divergent. _Dimensions._--Shell 0.06 long, 0.1 broad; horn and feet 0.05 to 0.07 long.