Lychnocanium tridentatum, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 80, Taf. vii. fig. 4.
Shell smooth, three-sided pyramidal, with deep collar stricture. Relative length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, with a conical horn of the same length, and some small accessory thorns. Thorax tetrahedral, with three smooth hyaline walls, bearing only a single series of small pores on each side of the three prominent ribs, which are prolonged into three strong prismatic curved feet of twice the length, with the convexity external. A group of small pores and a strong triangular tooth at the base of each foot.
Dimensions.—Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.08 broad.
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.)
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.