Page:Scientific results HMS Challenger vol 18 part 2.djvu/786

1662 1. Pharyngella monoceros, n. sp.

Shell ovate, slightly compressed, with a single large tooth on the dorsal corner of the peristome. The tooth is cylindro-conical, half as long as the shell, straight or slightly curved, and lies in the main axis of the shell. Pharynx cylindrical, straight, half as long as the shell-radius. This species is very similar to Challengeria tritonis (Pl. 99, fig. 5), and to the common cosmopolitan Challengeria naresii, but differs generically from them in the possession of the pharynx.

Dimensions.—Diameter of the shell 0.25 to 0.28; length of the tooth 0.14.

Habitat.—Tropical Atlantic, Station 348, depth 2450 fathoms.

2. Pharyngella gastrula, n. sp. (Pl. 99, fig. 18).

Shell ovate. Peristome with two parallel, vertical, straight, pointed teeth, which are half as long as the shell-radius. Pharynx of the same length, cylindrical or funnel-shaped, its outer aperture scarcely broader than the inner.

Dimensions.—Length of the shell 0.3 to 36, breadth 0.24 to 0.3; teeth and pharynx 0.07 to 0.09.

Habitat.—North Atlantic, Færöe Channel (Gulf Stream), John Murray, depth 600 fathoms.

3. Pharyngella invaginata, n. sp.

Shell circular, slightly compressed or nearly spherical. Peristome with two parallel, vertical, straight, pointed teeth, which are about as long as the shell-radius. Pharynx of the same length, funnel-shaped; its outer aperture twice as broad as the inner.

Dimensions.—Diameter of the shell 0.2 to 0.22, teeth and pharynx 0.05.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

4. Pharyngella gastræa, n. sp. (Pl. 99, fig. 17).

Shell broad, ovate or nearly circular, lenticular, strongly compressed. Peristome with two parallel, pointed teeth, which are nearly as long as the shell-radius, slightly curved, and obliquely inclined over the mouth. Pharynx half as long, cylindrical, obliquely descending; its outer and inner apertures of equal breadth.

Dimensions.—Diameter of the shell 0.3 to 0.33, teeth 0.12, pharynx 0.06.

Habitat.—South Atlantic, Stations 328 to 334, surface.

Definition.— with a pharynx, with teeth on the mouth and marginal spines.

The genus Porcupinia differs from the preceding Pharyngella in the development