_Habitat._--Fossil in Barbados. Subgenus 2. _Lamprotripus_, Haeckel, 1881, Prodromus, p. 432. _Definition._--Shell spiny or thorny, with prominent spines on the edges of the three thoracic ribs. (Commonly one larger and a few smaller horns or spines on the cephalis.) {1200}17. _Dictyophimus triserratus_, n. sp. (Pl. 61, fig. 17). Shell three-sided pyramidal, with slight collar stricture. Relative length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis small, subspherical, with a large pyramidal horn three times as long. Thorax with much larger, irregular roundish, double-edged pores, and three prominent, serrate ribs, which are prolonged into three pyramidal strongly divergent feet of the same length. _Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.09 broad. _Habitat._--Central Pacific, Station 274, depth 2750 fathoms. 18. _Dictyophimus bicornis_, n. sp. Shell thorny, with deep collar stricture. Relative length of the two joints = 2 : 3, breadth = 2 : 3. Cephalis nearly as large as the thorax, subglobular, with numerous small, circular pores, and two divergent pyramidal horns of half the length (a major occipital and a minor frontal horn). Thorax three-sided pyramidal, with larger irregular pores and three serrate ribs, which are prolonged into three prismatic spiny feet of half the length. (Differs from the similar _Dictyophimus sphærocephalus_, Pl. 57, fig. 10, mainly in the double horn and the spinulate feet.) _Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.08 long, 0.07 broad. _Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. 19. _Dictyophimus pocillum_, Ehrenberg. _Dictyophimus pocillum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 68, Taf. v. fig. 6. Shell thorny, with distinct collar stricture. Relative length of the two joints = 1 : 5, breadth = 1 : 5. Cephalis nearly spherical, with numerous small conical spines. Thorax flat, three-sided pyramidal with large, irregular, roundish pores, and three strong, widely divergent, spinulate ribs, which are prolonged into three prismatic spinulate feet of the same length. _Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.15 long, 0.15 broad. _Habitat._--Fossil in Barbados. 20. _Dictyophimus cienkowskii_, n. sp. (Pl. 60, fig. 1). _Lamprotripus squarrosus_, Haeckel, 1881, Prodromus et Atlas. Shell spiny, flatly pyramidal, with slight collar stricture. Relative length of the two joints = 1 : 3, breadth = 2 : 6. Cephalis flat, cap-shaped, three times as long as broad, with numerous bristle-shaped spines three times as long. Thorax also spiny, with irregular, very large, polygonal meshes and thin bars; its three ribs prolonged into three very long and thin, widely divergent, prismatic feet, bearing numerous long spines on the three edges. _Dimensions._--Cephalis 0.025 long, 0.05 broad; thorax 0.075 long, 0.15 broad. _Habitat._--North Pacific, Station 250, surface.