Page:Scientific results HMS Challenger vol 18 part 1.djvu/441

Rh Dimensions.—Diameter of the outer shell 0.08 to 0.12, inner 0.06 to 0.08; pores of the former 0.015 to 0.02, of the latter 0.007 to 0.012; length of the spines 0.02.

Habitat.—Central Pacific, Stations 268 to 274, surface.

Definition.—Pores of the cortical shell regular, of nearly equal size and similar form; the spines not covering the entire surface, but scattered at intervals (their number smaller than that of the nodal-points of the network).

10. Haliomma circumtextum, n. sp. (Pl. 28, figs. 7, 7a).

Cortical shell very delicate, with thin thread-like bars, and regular, hexagonal pores, little larger than the thick-walled medullary shell (= 7 : 6). Pores of the latter regular, circular, double-edged, with hexagonal frames, of the same breadth as the bars; from all the hexagon-corners arise thin bristle-shaped, radial spines, twice as long as the diameter of the pores, becoming connected at equal distances from the centre by tangential threads, regularly disposed, forming the cortical shell. Twelve strong, three-sided pyramidal, radial spines, as broad at the base as one mesh, and about half as long as the radius of the shell.

Dimensions.—Diameter of the outer shell 0.14, of the inner 0.12; pores of the former 0.012, of the latter 0.005; length of the radial spines 0.04, basal breadth 0.012.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

11. Haliomma duodecinum, n. sp.

Cortical shell thick walled, three times as broad as the medullary shell. Both shells with regular, circular pores, twice as broad as the bars; eight to ten on the radius of the outer, five to six on the radius of the inner shell. Twelve conical, regularly disposed radial spines, as long as the radius, and as broad at the base as one mesh.

Dimensions.—Diameter of the outer shell 0.12, of the inner 0.04; pores of the former 0.005, of the latter 0.002; length of the spines 0.05, basal breadth 0.005.

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

12. Haliomma megaporum, Ehrenberg.

Haliomma megaporum, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 313.

Cortical shell thin walled, three times as broad as the medullary shell; the pores regular, circular, three to four on the radius, eight times as broad as the bars, quite as broad as the medullary shell, the pores of which are much smaller, twice as broad as the bars. Eight radial spines regularly disposed, conical, as long as the radius. (As the diagnosis of Ehrenberg is very