Definition.—Surface of the disk with elevated radial ribs or spines.
4. Phacodiscus echiniscus, n. sp.
Disk with spiny surface, four times as broad as the outer, and ten times as broad as the inner medullary shell. Pores irregularly roundish; fourteen to fifteen on the radius of the disk. Margin of the disk sharp, as in a biconvex lens.
Dimensions.—Diameter of the disk 0.3, of the outer medullary shell 0.75, of the inner 0.03; pores 0.007.
Habitat.—South Atlantic, Station 332, depth 2200 fathoms.
5. Phacodiscus clypeus, n. sp. (Pl. [35], figs. 6, 9).
Disk with radiated surface, four times as broad as the outer, and twelve times as broad as the inner medullary shell. Pores regularly circular; sixteen to eighteen on the radius of the disk; in the distal half disposed in sixty to seventy radial series, which are separated by prominent crests; the sharp margin therefore a little jagged.
Dimensions.—Diameter of the disk 0.2, of the outer medullary shell 0.05, of the inner 0.017; pores 0.006.
Habitat.—Pacific, central area, Station 266, depth 2750 fathoms.