Page:Scientific results HMS Challenger vol 18 part 2.djvu/206

1082 size. Apical horn pyramidal, about as long an the shell. Basal coronet with twenty to twenty-five slender, lamellar, pointed, vertical feet, longer than the shell.

Dimensions.—Shell 0.11 long, 0.12 broad; ring 0.07 long; horn 0.1; feet 0.12 to 0.18 long.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

Definition.— with numerous basal feet (eight to twelve or more). Galea without a horn.

The genus Tiarospyris has probably been derived from the preceding Sepalospyris by reduction and loss of the free apical horn; it therefore bears to it the same relation that the similar Gorgospyris does to Petalospyris.

1. Tiarospyris pervia, n. sp. (Pl. 87, fig. 7).

Shell nut-shaped, smooth, with deep sagittal stricture. Cephalis on the lateral sides with numerous small roundish pores, on each side of the ring with a pair of very large holes. Basal plate with two large collar pores. Cupola flat, cap-shaped, with two large parietal pores above the ring. Coronet with eight conical, slightly divergent feet, about one-fourth as long as the shell.

Dimensions.—Shell 0.08 long, 0.1 broad; ring 0.06 long; feet 0.02 long.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

2. Tiarospyris galea, n. sp.

Shell helmet-shaped, with deep sagittal stricture. Cephalis with irregular, polygonal pores; on each side of the ring two pairs of larger annular pores. Basal plate with four large pores. Cupola high, conical, nearly as long as the cephalis, separated from it by a distinct coronal stricture. Basal coronet with twelve to sixteen slender curved divergent feet, nearly as long as the shell.

Dimensions.—Shell 0.16 long, 0.12 broad; ring 0.1 long; feet 0.15 long.

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

3. Tiarospyris mitra, n. sp. (Pl. 87, figs. 9, 10).

Shell subspherical, smooth. Cephalis on the lateral sides with small roundish, double-contoured pores, on each side of the ring with three to five pairs of larger pores, each of which is closed by a thin fenestrated lamella (different on the frontal face, fig. 9, and the dorsal face, fig. 10). Cupola flat, cap-shaped, separated by a distinct coronal stricture, with similar pores. Basal coronet with, ten to twelve short conical convergent feet.

Dimensions.—Shell 0.11 long, 0.12 broad; ring 0.04 long; feet 0.02 long.

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