Page:Scientific results HMS Challenger vol 18 part 2.djvu/159

Rh primary ring. The vertical axis of the slender ovate shell is much greater than the transverse. The network is very delicate, with very small and numerous triangular or polygonal pores. The central capsule encloses peculiar concrements (Pl. 96, fig. 28).

1. Cephalospyris cancellata, n. sp. (Pl. 83, fig. 10).

Shell slender ovate, two and a half times as long as broad, with deep sagittal stricture and complete ring. Network very delicate, with very small and numerous, irregular polygonal pores. The two large apical holes are separated by a latticed triangular sagittal septum, the apex of which represents a rudimentary horn. Basal plate with two large collar holes. Three feet slightly curved, divergent, about half as long as the breadth of the shell; the caudal foot slender, much thinner than the two stout pyramidal pectoral feet.

Dimensions.—Shell 0.32 long, 0.13 broad.

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

2. Cephalospyris ovata, n. sp.

Shell slender, ovate, twice as long as broad, with deep sagittal stricture and complete ring. Network very delicate, with very small and numerous triangular pores (on both poles intermingled with irregular polygonal pores). The two large apical holes are separated by a latticed triangular sagittal septum, the upper edge of which is concave and bears two rudimentary horns. Basal plate with four large collar holes. Three feet latticed, slightly curved, convergent, scarcely one-eighth as long as the breadth of the shell. The central capsule filled up by concrements.

Dimensions.—Shell 0.32 long, 0.16 broad.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

3. Cephalospyris triangulata, n. sp. (Pl. 96, fig. 28).

Shell ovate, one and a half times as long as broad, with deep sagittal stricture and complete ring. Network very delicate and regular, with small triangular pores of equal size. The two large apical holes are separated by a latticed semilunar septum, the upper edge of which is concave, and bears two rudimentary horns. Basal plate with three large collar holes (?). Three feet latticed, conical, nearly parallel and vertical (the caudal curved), about half as long as the breadth of the shell. The ovate central capsule contains peculiar amyloidal concentric concrements.

Dimensions.—Shell 0.2 long, 0.14 broad.

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

Definition.— dipoda, with two descending lateral basal feet (probably corresponding to the pectoral feet of Cortina).