Page:Scientific results HMS Challenger vol 18 part 2.djvu/583

Rh Dimensions.—Length of the shell (with four joints) 0.2, breadth 0.1. Length of the single joints, a 0.02, b 0.05, c 0.06, d 0.07.

Habitat.—South Pacific, Station 300, depth 1375 fathoms.

2. Artophormis costata, n. sp.

Shell spindle-shaped, rough, with six distinct strictures, three times as long as broad. The length of the seven joints increases gradually; the last joint is twice as long as the fifth. Six prominent, radial ribs arise from the third stricture, and are prolonged into six slender, convergent, conical feet, as long as the sixth joint. Cephalis hemispherical, with a pyramidal horn of twice the length. Pores regular, circular.

Dimensions.—Length of the shell (with seven joints) 0.24, breadth 0.08. Length of the last joint 0.05.

Habitat.—South Pacific, Station 295, depth 1500 fathoms.

3. Artophormis barbadensis, Haeckel.

Calocyclas barbadensis, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 66, Taf. xviii. fig. 8.

Shell slenderly ovate, smooth, with three sharp strictures, twice as long as broad. Length of the four joints = 1 : 2 : 3 : 2. Nine prominent longitudinal ribs arise from the third joint, and are prolonged into nine slender, conical, little convergent feet. Cephalis hemispherical, with a conical horn of the same length. Pores subregular, circular, twice as large in the third joint as in the second; the fourth joint bears above a circle of nine very large pores (alternate with the nine ribs), and below two or three circles of smaller pores (eighteen to twenty-seven in the circumference). Mouth somewhat constricted. The figure of Ehrenberg is incomplete, the horn of the cephalis and the nine feet being broken off.

Dimensions.—Length of the shell (with four joints) 0.16, breadth 0.08. Length of the single joints, a 0.02, b 0.04, c 0.06, d 0.04.

Habitat.—Fossil in Barbados.

Definition.— (vel Stichocyrtida multiradiata aperta) with ovate or spindle-shaped shell, without lateral ribs. Mouth constricted, with a corona of terminal feet.

The genus Cyrtophormis may be derived from the preceding Artophormis by reduction of the lateral ribs, whilst the terminal feet (as their free prolongations) remain, and form a corona around the mouth. Sometimes also each constriction bears