Page:Scientific results HMS Challenger vol 18 part 2.djvu/339

Rh 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.

4. Lampromitra pyramidalis, n. sp.

Shell flat, pyramidal, smooth, with slight collar stricture. Length of the two joints = 1 : 4, breadth = 1 : 9. Cephalis subspherical, with an oblique pyramidal horn of twice the length, and small circular pores. Thorax with three strong, divergent, straight ribs and three flat triangular sides between them, with subregular hexagonal pores, increasing in size towards the mouth. Peristome with a simple coronal of large and numerous divergent, conical spines, half as long as the shell.

Dimensions.—Cephalis 0.02 long, 0.02 broad; thorax 0.09 long, 0.18 broad.

Habitat.—South Atlantic, Station 325, depth 2650 fathoms.

5. Lampromitra huxleyi, Haeckel (Pl. 59, fig. 1).

Eucecryphalus huxleyi, Haeckel, 1879, Natürl. Schöpfungsgesch., Edit. vii. Taf. xvi. fig. 9.

Shell flat, conical, spiny, with slight collar stricture. Length of the two joints = 1 : 3, breadth = 1 : 8. Cephalis hemispherical, with a short conical horn of the same length. Thorax with irregular polygonal pores. Peristome with three coronals of divergent bristle-shaped spines; the first directed obliquely upwards, the second outwards, and the third nearly vertically, downwards; the bristles of the latter are much longer, about as long as the height of the shell.

Dimensions.—Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.16 broad.

Habitat.—Australia (east coast), Station 169, surface.