Shell three-sided pyramidal, with a deep collar stricture. Relative length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis hemispherical, with a thin horn of the same length. Thorax with three curved ribs, which are prolonged into three divergent angular feet of the same length. Pores irregular roundish. _Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.05 long, 0.08 broad. _Habitat._--North Pacific, Station 240, surface, Kamtschatka (Bailey). 10. _Dictyophimus cortina_, n. sp. (Pl. 61, fig. 1). Shell three-sided pyramidal, with distinct collar stricture. Relative length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, with a pyramidal horn of half the length. Thorax {1198}with much larger irregular roundish pores and three prominent ribs, which are prolonged into three stout, club-shaped, strongly divergent feet of the same length. Mouth widely open, elegantly coronate, with a circle of numerous small cilia. _Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.08 broad. _Habitat._--Central Pacific, Station 272, depth 2600 fathoms. 11. _Dictyophimus arabicus_, Haeckel. _Lychnocanium arabicum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 296, Taf. x. fig. 3. Shell smooth, three-sided pyramidal, with deep collar stricture. Relative length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, with a slender horn of the same length. Thorax with much larger, irregular roundish pores, and three widely divergent ribs, which are prolonged into three slender, somewhat recurved feet of about the same length. _Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.07 long, 0.09 broad. _Habitat._--Indian Ocean, Zanzibar (Pullen), depth 2200 fathoms. 12. _Dictyophimus platycephalus_, n. sp. (Pl. 60, figs. 4, 5). Shell smooth, flat, three-sided pyramidal, with distinct collar stricture. Relative length of the two joints = 1 : 3, breadth = 3 : 9. Cephalis flat, cap-shaped, three times as broad as long, with a slender conical horn of the same length. Thorax flatly vaulted, with much larger, irregular roundish, double-edged pores, and three widely divergent ribs, which are prolonged into three slender conical feet of the same length. Central capsule in the cephalis flat, discoidal, with a discoidal nucleus of half the size, and with four large pear-shaped cæcal sacs depending into the thorax, each of which contains a large oil globule (fig. 4). _Dimensions._--Cephalis 0.02 long, 0.07 broad; thorax 0.06 long, 0.18 broad. _Habitat._--North Atlantic, Canary Islands (Lanzerote), Haeckel, surface. 13. _Dictyophimus brandtii_, n. sp. (Pl. 60, fig. 6).