Page:Scientific results HMS Challenger vol 18 part 1.djvu/1061

Rh as broad as the irregular sutural pores. Radial spines compressed, sword-shaped, about as long as the diameter of the shell.

Dimensions.—Diameter of the outer shell 0.09, of the inner 0.04.

Habitat.—South Atlantic, Station 332, surface.

4. Phractopelta tessaraspis, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with four crossed, quadrangular, aspinal pores, the two opposite of which are much larger than the two others. Sutural pores small, roundish. Radial spines compressed, linear, about twice as long as the diameter of the shell.

Dimensions.—Diameter of the outer shell 0.084, of the inner 0.032.

Habitat.—North Pacific (off Japan), Station 238, surface.

5. Phractopelta tetradopora, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with four crossed quadrangular (or nearly circular) aspinal pores, all of nearly the same size. Sutural pores polygonal or roundish. Radial spines cylindrical, two to three times as long as the diameter of the shell.

Dimensions.—Diameter of the outer shell 0.11, of the inner 0.045.

Habitat.—North Pacific, Station 253, surface.

6. Phractopelta hexadopora, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with six aspinal pores, the two opposite of which are much larger than the four others. Sutural pores small, roundish. Radial spines compressed, two-edged, larger than the diameter of the shell.

Dimensions.—Diameter of the outer shell 0.1, of the inner 0.04.

Habitat.—Central Pacific, Station 272, surface.

7. Phractopelta octadopora, n. sp.

Outer shell composed of twenty plates, the meeting condyles of which are separated by permanent sutures. Each plate commonly with eight aspinal pores, the four crossed being larger than the four others alternating with them. Sutural pores irregular. Radial spines conical, shorter than the diameter of the shell.

Dimensions.—Diameter of the outer shell 0.12, of the inner 0.04.

Habitat.—Indian Ocean (Cocos Islands, surface), Rabbe.