Page:Scientific results HMS Challenger vol 18 part 2.djvu/584

1460 a corona of spines. It corresponds to Calocyclas among the Tricyrtida and Anthocyrtis among the Dicyrtida.

Definition.—Shell with six (sometimes five or seven) feet on the peristome (three perradial alternate with three interradial).

1. Cyrtophormis armata, n. sp. (Pl. 78, fig. 17).

Shell spiny, spindle-shaped, with three annular septa. Length of the four joints = 3 : 4 : 5 : 6. The third joint is the broadest, being twice as broad as the constricted mouth. Pores irregular, roundish. Cephalis conical, armed with a bunch of strong, conical spines, and distinguished by double-contoured pores. Peristome with six (sometimes five or seven) triangular, vertical, parallel, or slightly divergent feet.

Dimensions.—Length of the shell (with four joints) 0.18, breadth 0.09. Length of the single joints, a 0.03, b 0.04, c 0.05, d 0.06.

Habitat.—Central Pacific, Station 266, depth 2750 fathoms.

2. Cyrtophormis ovata, n. sp.

Shell rough, ovate, very thick-walled, with three distinct strictures. Length of the four joints = 1 : 1 : 2 : 3. The fourth joint is the broadest, inversely hemispherical, and three times as broad as the constricted mouth. Pores regular, circular, hexagonally framed. Cephalis hemispherical, with a pyramidal horn of the same length. Peristome with a coronal of six short, conical, curved, outwardly convex teeth.

Dimensions.—Length of the shell (with four joints) 0.2, breadth 0.14. Length of the single joints, a 0.02, b 0.03, c 0.06, d 0.09.

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

Definition.—Shell with nine (sometimes eight or ten) feet on the peristome (three perradial alternate with six interradial).

3. Cyrtophormis cingulata, n. sp. (Pl. 78, fig. 18).

Shell spiny, spindle-shaped, with three internal annular septa, and three external girdles of spines. The second and third joints are of nearly equal length, twice as broad as the first, and half as broad as the fourth joint. The third joint is the broadest, and twice as broad as the constricted mouth. Pores subregular, circular. Cephalis hemispherical, with a large apical horn, and