Dimensions.—Cephalis 0.03 long, 0.07 broad; thorax 0.06 long, 0.2 broad.
Habitat.—Central Pacific, Station 271, depth 2425 fathoms.
2. Lampromitra quadricuspis (Pl. [58], fig. 7).
Shell flat, conical, with sharp collar stricture. Length of the two joints = 1 : 3, breadth = 2 : 10. Cephalis hemispherical, with subregular circular pores and an oblique, conical, occipital horn of twice the length, bearing three divergent lateral branches, which are directed upwards, and correspond to the three thoracic ribs. Further down, near the collar stricture, a short divergent frontal horn arises. Thorax with irregular roundish pores of different sizes, three to six times as broad as the bars. Peristome with a simple coronal of short, conical, divergent spines, about as long as the diameter of the cephalis.
Dimensions.—Cephalis 0.02 long, 0.04 broad; thorax 0.06 long, 0.2 broad.
Habitat.—North Atlantic, Canary Islands, surface.
3. Lampromitra furcata, n. sp. (Pl. [58], fig. 8).
Shell flat, conical, with deep collar stricture, very similar in form and structure to the preceding species; differs from it in the shape of the peristome and the armature of the cephalis, which bears a conical, forked, occipital horn of the same length, and a small rudimentary divergent frontal horn. Length of the two joints = 1 : 2, breadth = 1 : 6. The four pores of the collar septum (two larger cardinal and two smaller jugular) exhibit in this species a peculiar asymmetry (fig. 8). The peristome bears a simple coronal of spines as long as the diameter of the cephalis. The major part of them is forked, some irregularly branched.
Dimensions.—Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.18 broad.
Habitat.—South Pacific, Station 298, depth 2225 fathoms.