Habitat.—North Pacific, Station 244, depth 2900 fathoms.
6. Sethodiscus micrococcus, n. sp.
Disk with smooth surface, five times as broad as the medullary shell. Pores irregular, roundish, very small; twenty-six to twenty-eight on the radius of the disk. (The pores of the small medullary shell are regularly circular, of the same size as those of the disk.)
Dimensions.—Diameter of the disk 0.2, of the medullary shell 0.04, of the pores 0.002.
Habitat.—South Atlantic, Station 335, depth 1425 fathoms.
Subgenus 2. Sethodisculus, Haeckel.
Definition.—Surface of the disk with elevated radial ribs or spines.
7. Sethodiscus radiatus, Haeckel.
Haliomma radians, Ehrenberg, 1854, Mikrogeol., Taf. xix. fig. 50.
Haliomma radiatum, Ehrenberg, 1854, Mikrogeol., Taf. xxi. fig. 54.