Page:Scientific results HMS Challenger vol 18 part 1.djvu/365

Rh one mesh; two opposite larger spines as long as the diameter of the shell, two smaller only as long as the radius.

Dimensions.—Diameter of the shell 0.15, pores 0.01, bars 0.005; length of the major spines 0.16, minor 0.08.

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

2. Staurostylus latinus, n. sp.

Shell thin walled, smooth, with regular, circular, double-edged pores, three times as broad as the bars; twelve to fourteen on the quadrant. Spines conical, twice as broad at the base as one mesh; two opposite larger spines as long as the radius of the shell, two smaller only one-third as long.

Dimensions.—Diameter of the shell 0.24, pores 0.012, bars 0.004; length of the major spines 0.12, minor 0.04.

Habitat.—South Pacific, Station 295, depth 1500 fathoms.

3. Staurostylus germanicus, n. sp.

Shell thick walled, covered with bristle-shaped by-spines, half as long as the radius. Pores regular, circular, hexagonally framed, twice as broad as the bars; eight to ten on the quadrant. From each hexagon-corner arises one short by-spine. Four main spines three-sided pyramidal, as broad at the base as one mesh; two opposite larger spines one and a half times as long as the radius, two smaller two-thirds as long.

Dimensions.—Diameter of the shell 0.16, pores 0.008, bars 0.004; length of the major spines 0.12, minor 0.08.

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

Definition.— with one single lattice-sphere and four crossed spines, one of which is much larger than the other three.

The genus Stylostaurus differs from the preceding in the extraordinary development of one of the four spines, which is much longer than the other three; these may be equal or different.

1. Stylostaurus caudatus, n. sp. (Pl. 13, fig. 7).

Shell thick walled, smooth, with regular, circular, hexagonally framed pores, twice as broad as the bars; five to six on the quadrant. Spines three-sided pyramidal, as broad at the base as