_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. 3. _Triceraspyris didiceros_, Haeckel. _Ceratospyris didiceros_, Ehrenberg, 1875, Abhandl. d. Akad. d. Wiss. Berlin, p. 66, Taf. xxi. fig. 6. Shell nut-shaped, thorny, with superficial sagittal stricture. Pores large, irregular roundish. Basal plate with four larger pores. Apical horn and caudal foot small, conical, shorter than half the shell. The two frontal horns longer, slender conical. The two pectoral feet very large, cylindrical, nearly parallel, vertical, slightly curved, twice to three times as long as the shell. _Dimensions._--Shell 0.07 long, 0.09 broad; two sagittal spines 0.02 long, two lateral horns 0.04 long, two lateral feet 0.15 to 0.25 long. _Habitat._--Fossil in Barbados. Subgenus 2. _Triospyrium_, Haeckel. _Definition._--Horns simple, not branched; feet forked or branched. {1031}4. _Triceraspyris furcata_, Haeckel. _Ceratospyris furcata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. xx. fig. 8. Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores numerous, irregular roundish. Basal plate with four large pores. Three horns small, conical, shorter than half the shell. Three feet large, cylindrical, curved, about twice as long as the shell, forked at the distal end. _Dimensions._--Shell 0.07 long, 0.08 broad; horns 0.02 long, feet 0.1 to 0.12 long. _Habitat._--Fossil in Barbados. 5. _Triceraspyris giraffa_, n. sp. (Pl. 84, fig. 11). Shell nut-shaped, mammillate, with slight sagittal stricture. Pores numerous, subregular circular. Basal plate with nine pores (three larger central and three alternate pairs of smaller peripheral, as in Pl. 87, fig. 2). Three horns equal, straight, divergent, shorter than the shell, in the basal half cylindrical, in the distal half spindle-shaped. Three feet cylindrical, twice as long as the shell, nearly parallel, vertical, at the distal end divergent, with a recurved branch near the base. _Dimensions._--Shell 0.08 long, 0.1 broad; horns 0.05 to 0.07 long, feet 0.16 long. _Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. 6. _Triceraspyris gazella_, n. sp. (Pl. 84, fig. 9). Shell nut-shaped, tuberculate, with sharp sagittal stricture. Pores large, irregular roundish; two or three pairs of larger pores on each side of the ring. Basal plate with three large triangular pores. Three horns simple, about as long as the shell, the apical straight, the two frontal elegantly curved. Three feet somewhat longer, slender, curved, with a recurved branch near the base, repeatedly forked at the distal end. _Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.05 long, feet 0.08 long. _Habitat._--Indian Ocean (Cocos Islands), surface (Rabbe). 7. _Triceraspyris corallorrhiza_, n. sp. (Pl. 84, fig. 12).