Page:Scientific results HMS Challenger vol 18 part 2.djvu/644

1520 4. Artocapsa quadricamera, n. sp.

Shell spindle-shaped, smooth, with three sharp strictures. Length of the four joints = 2 : 3 : 4 : 8. The third joint is the broadest. The fourth joint is inversely conical, nearly as long as the three other joints together, and bears a strong, conical, basal spine, of half the length. The cephalis is small, subspherical, and bears a conical horn of the same length. Pores subregular, circular.

Dimensions.—Length of the shell (with four joints) 0.17, breadth 0.08. Length of the single joints, a 0.02, b 0.03, c 0.04, d 0.08.

Habitat.—Fossil in Barbados.

5. Artocapsa armata, n. sp.

Shell slender, inversely ovate, spiny, with six deep strictures. Length of the seven joints = 2 : 4 : 6 : 5 : 4 : 3 : 2. The third joint is the broadest, inflated, and much larger than the four following, which gradually decrease in size. The small, hemispherical cephalis bears a stout pyramidal horn of twice the length. The last hemispherical joint is armed with a bunch of stout spines, one of which is much the larger, and as long as the third joint. Pores irregular, roundish.

Dimensions.—Length of the shell (with seven joints) 0.26, breadth 0.12. Length of the single joints, a 0.02, b 0.04, c 0.06, d 0.05, e 0.04, f 0.03, g 0.02.

Habitat.—Western Tropical Pacific, Station 225, depth 4575 fathoms.

6. Artocapsa octocamera, n. sp.

Shell subcylindrical, smooth, with seven internal annular septa. Five joints (the third to the seventh) are nearly equal in size, while the second and eighth are cupola-shaped, somewhat longer. The cephalis is smaller, with a conical horn of the same length. The last joint bears a bunch of divergent, conical spines, of different lengths. Pores small, regular, circular.

Dimensions.—Length of the shell (with eight joints) 0.16, breadth 0.08. Length of the cephalis 0.016, second and eighth joints 0.033, each of the five other joints 0.022.

Habitat.—South Pacific, Station 285, depth 2375 fathoms.

7. Artocapsa elegans, n. sp. (Pl. 76, fig. 8).

Shell spindle-shaped, smooth, with eight internal, broad, annular septa. The second and third joints are the largest, the fourth and fifth of medium size, while the cephalis and the four last joints are nearly equal in length, and much shorter. The third joint is the largest. The subspherical cephalis bears a bristle-shaped horn of the same length, while the last joint is armed with a bunch of conical spines. Pores small, in the upper half of the shell regular, hexagonal, in the lower half irregular.

Dimensions.—Length of the shell (with nine joints) 0.2, breadth 0.09. Length of the first and the four last joints, each 0.014; of the fourth and fifth, each 0.02; of the third 0.04, second 0.05.

Habitat.—Central Pacific, Station 274, depth 2750 fathoms.