Page:Scientific results HMS Challenger vol 18 part 1.djvu/335

Rh Dimensions.—Diameter of the sphere 0.18, pores 0.01 to 0.015, bars 0.008; length of the polar spines 0.25 to 0.3, thickness 0.02.

Habitat.—Indian Ocean, surface; Ceylon, Haeckel.

Definition.— with one single lattice-sphere and two free spines of different size or form.

The genus Xiphostylus differs from the foregoing Xiphosphæra in the unequal size or form of both polar spines, which become more or less differentiated.

Definition.—Pores of the spherical shell regular, of nearly equal size and form; surface smooth or a little rough, without spines or thorns.

1. Xiphostylus alcedo, n. sp. (Pl. 13, fig. 4).

Pores regular, circular, with elevated hexagonal frames, twice as broad as the bars. Eight to ten pores on the half equator. Surface smooth. Polar spines three-sided pyramidal, as broad at the base as one hexagon; the major spine four to five times as long as the minor, which is about equal to the radius of the sphere.

Dimensions.—Diameter of the sphere 0.12, pores 0.012, bars 0.006; length of the major polar spine 0.16 to 0.2, of the minor 0.04 to 0.06, basal breadth 0.02.

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

2. Xiphostylus phasianus, n. sp. (Pl. 13, fig. 9).

Pores regular, circular, twice as broad as the bars. Eight to ten pores on the half equator. Outer opening of each pore elegantly lobed, with eight indentations. Surface a little rough. Polar spines very unequal; major spine sword-like, sharply edged, about as long as the diameter of the sphere; minor spine scarcely half so long, pommel-shaped, with nine (?) wing-like edges.

Dimensions.—Diameter of the sphere 0.13, inner circular opening of the pores 0.01, outer eight-lobed opening 0.015, bars 0.005; length of the major polar spine 0.14, of the minor 0.06, breadth 0.03.

Habitat.—Australian Sea, Station 162, surface.

3. Xiphostylus motacilla, n. sp.

Pores regular, circular, three times as broad as the bars; sixteen to twenty on the half equator. Surface smooth. Polar spines compressed, two-edged, at the base three to four times as broad as