Page:Scientific results HMS Challenger vol 18 part 1.djvu/669

Rh lenticular; the latter is connected with the lenticular phacoid shell (or cortical shell) by radial beams.

1. Coccodiscus lamarckii, n. sp. (Pl. 36, fig. 1).

Phacoid shell (or lenticular porous cortical shell) very thick walled (as thick as one ring), three times as broad as the outer and seven times as broad as the inner medullary shell, surrounded by two to three chambered rings of equal breadth, each of which is divided by piercing radial beams into thirty-six to forty square chambers. Margin of the disk circular, smooth. Pores regular, circular, of equal size; ten on the radius of the phacoid shell, two on the breadth of each chamber.

Dimensions.—Diameter of the disk (with two rings) 0.2, of the phacoid shell 0.14, outer medullary shell 0.05, inner 0.02.

Habitat.—Western Tropical Pacific, Station 220, depth 1100 fathoms.

2. Coccodiscus darwinii, Haeckel.

Coccodiscus darwinii, Haeckel, 1862, Monogr. d. Radiol., p. 486, Taf. xxviii. figs. 11, 12.

Phacoid shell three times as broad as the outer and nine times as broad as the inner medullary shell, surrounded by five to eight chambered rings of equal breadth, each of which is divided by forty piercing radial beams into forty square chambers of equal size. Margin of the disk smooth, circular. Pores irregular, roundish, of unequal size; eleven on the radius of the phacoid shell, one to two on each chamber.

Dimensions.—Diameter of the disk (with eight rings) 0.32, of the phacoid shell 0.11, outer medullary shell 0.036, inner 0.012.

Habitat.—Mediterranean, Messina, surface.

3. Coccodiscus goethei, n. sp. (Pl. 36, fig. 2).

Phacoid shell two and a half times as broad as the outer and five times as broad as the inner medullary shell, surrounded by three to seven chambered rings of equal breadth, each of which is divided by piercing radial beams into sixty to eighty chambers. Margin of the disk thorny. Pores regular, circular; eight on the radius of the phacoid shell, a single one on the breadth of each chamber.

Dimensions.—Diameter of the disk (with seven rings) 0.25, of the phacoid shell 0.1, of the medullary shell 0.04, inner 0.02.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

Definition.— with solid radial spines on the margin of the circular disk, situated in its equatorial plane (without chambered arms).