Page:Scientific results HMS Challenger vol 18 part 2.djvu/588

1464 twice as long as the first and the third, and armed with six divergent, stout, pyramidal, radial spines or wings of the same length. Cephalis flat, cap-shaped, with an oblique pyramidal horn of twice the length. Pores regular, circular, hexagonally framed.

Dimensions.—Length of the shell (with four joints) 0.18, breadth 0.12. Length of the single joints, a 0.02, b 0.04, c 0.02, d 0.1.

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

2. Artophæna senaria, n. sp.

Shell pear-shaped, with five distinct strictures. Length of the four middle joints little different. The fifth joint is the broadest. From the first stricture there arise six radial ribs, which at the fourth are prominent as six short, conical, divergent spines. The last joint is inversely hemispherical, twice as long as the preceding. Cephalis hemispherical, with a conical horn of the same length. Pores regular, circular.

Dimensions.—Length of the shell (with six joints) 0.14, breadth 0.09; of each joint 0.02, of the last 0.04.

Habitat.—Central Pacific, Station 273, depth 2350 fathoms.

3. Artophæna hexalatractus, n. sp.

Shell spindle-shaped, with three sharp strictures, and six triangular, latticed, divergent wings, which arise from the collar stricture and descend along the two middle joints. Their terminal points fall into the same plane as the basal end of the fourth inversely conical joint. Length of the four joints = 1 : 2 : 4 : 2. Cephalis hemispherical, with a conical horn of the same length. (Similar to Theophæna hexaptera, Pl. 68, fig. 13, but with three distinct internal annular septa, corresponding to the three external strictures.)

Dimensions.—Length of the shell (with four joints) 0.18, breadth 0.08. Length of the four single joints, a 0.02, b 0.04, c 0.08, d 0.04.

Habitat.—South Pacific (off Juan Fernandez), Station 300, depth 1375 fathoms.

4. Artophæna hexapodiscus, n. sp.

Shell ovate, without external strictures, but with five internal annular septa. Length of the six joints = 1 : 2 : 3 : 4 : 3 : 6. Cephalis hemispherical, with a stout conical horn of twice the length. The last joint is the broadest, inversely hemispherical. From the fourth and fifth joints arise six divergent ribs, which are prolonged over the fifth stricture into six triangular, divergent, fenestrated feet, about as long as the last joint. Pores in the upper half of the shell regular, circular, in the lower half irregular, roundish.

Dimensions.—Length of the shell (with six joints) 0.2, breadth 0.12. Length of the single joints, a 0.015, b 0.025, c 0.03, d 0.04, e 0.03, f 0.06.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.