Radial proportion of the four spheres = 1 : 2 : 3 : 4. All four shells of the same structure, thin-walled, with irregular roundish pores, two to four times as broad as the bars; the size of the pores increasing gradually from the inner to the outer shell. Surface smooth. Distance between each two shells equal to the diameter of the innermost.
Dimensions.—Diameter of the four spheres—(A) 0.12, (B) 0.09, (C) 0.06, (D) 0.03.
Habitat.—Central Pacific, Station 268, depth 2900 fathoms; also fossil in Barbados.
6. Cromyosphæra antarctica, n. sp..
Radial proportion of the four spheres = 1 : 2 : 5 : 7. Both cortical shells with irregular polygonal roundish pores; the outermost with thinner bars and rough surface, the inner with thicker bars. Both medullary shells with irregular roundish pores.
Dimensions.—Diameter of the four spheres—(A) 0.18, (B) 0.12, (C) 0.05, (D) 0.025.
Habitat.—Antarctic Ocean; in very large number, together with Rhizosphæra antarctica, in the diatomaceous ooze of Station 157 (3rd March 1874); depth 1950 fathoms.
Subfamily Caryosphærida,[[38]] Haeckel, 1881, Prodromus, pp. 449, 454.
Definition.—Liosphærida with numerous (five or more) concentric spherical latticed shells, united by radial beams.