Page:Scientific results HMS Challenger vol 18 part 2.djvu/599

Rh in the sixth joint. Horn small, conical. This species differs from all others in the subregular square form of the small pores.

Dimensions.—Length of the shell (with seven joints) 0.15; length of the seventh joint 0.024, breadth 0.12.

Habitat.—Central Pacific, Station 271 to 274, depth 2350 to 2750 fathoms.

22. Lithostrobus hexagonalis, n. sp. (Pl. 79, fig. 20).

Shell broad, conical, smooth, with straight axis, and five to eight prominent girdles between six and nine constricted broad joints. The first and the third joints are half as long as the second, the fourth, and each of the following joints. The sixth joint is five times as broad as long. Pores subregular, hexagonal, in regular transverse rows; three to four rows in the first and the second joints, six to eight in the third, the fourth, and each following joint. Cephalis with some small spines, and a larger, oblique, curved horn.

Dimensions.—Length of the shell (with six joints) 0.2; length of the sixth joint 0.04, breadth 0.2.

Habitat.—Central Pacific, Station 272, depth 2600 fathoms.

Definition.—Shell conical, with straight axis, joints of different lengths. Cephalis lobate, with some irregular constrictions. (Perhaps derived from ?).

23. Lithostrobus botryocyrtis, n. sp. (Pl. 79, figs. 18, 19).

Shell slender, conical, smooth, with straight axis, and three deep strictures. Joints of different lengths. The length of the fourth joint equals two-thirds of its breadth, and of the length of the three preceding joints together. Each of the latter bears three transverse rows of small, quadrangular pores, the fourth joint has six rows. The cephalis is irregularly lobate, with four to six prominent lobes, and two small divergent horns (fig. 19).

Dimensions.—Length of the shell (with four joints) 0.1; length of the fourth joint 0.04, breadth 0.06.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

24. Lithostrobus lithobotrys, n. sp. (Pl. 79, fig. 17).

Shell slender, conical, smooth, with straight axis, and four deep strictures. Joints of different lengths, gradually increasing towards the mouth, the length of the fifth joint equals half its breadth, and one-third of the length of the whole shell. The single joints bear each four or five transverse rows of small, roundish pores. Cephalis irregularly lobate, with four to six prominent lobes, and the same number of small, conical horns.