Subfamily Staurocromyida, Haeckel, 1881, Prodromus, pp. 449, 453

Definition.—Staurosphærida with four concentric spherical lattice-shells.

Genus 68. Staurocromyum, Haeckel, 1881, Prodromus, p. 453.

Definition.—Staurosphærida with four concentric lattice-spheres and four crossed, equal, simple spines.

The genus Staurocromyum has arisen probably from Stauracontium by duplication of the cortical shell, two concentric shells lying within, two others outside the central capsule.

1. Staurocromyum quadruplex, n. sp.

Radial proportion of the four spheres = 1 : 2 : 8 : 10. Both medullary shells with very small, regular, circular pores. Inner cortical shell with regular, circular, hexagonally-framed pores, twice as broad as the bars; from each hexagon-corner arises a small by-spine, and these, connected by tangential branches at equal distances from the centre, form the delicate outer cortical shell, with spiny surface. Four main spines three-sided pyramidal, as long as the shell radius.

Dimensions.—Diameter of the four shells—(A) 0.25, (B) 0.2, (C) 0.05, (D) 0.025; length of the spines 0.12.

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

2. Staurocromyum quadrispinum, n. sp.

Radial proportion of the four spheres = 1 : 3 : 9 : 12. Both medullary shells with small, regular, circular pores. Both cortical shells with irregular, roundish pores. Surface covered with short, conical by-spines. Four main spines cylindro-conical, somewhat longer than the shell diameter.

Dimensions.—Diameter of the four shells—(A) 0.24, (B) 0.18, (C) 0.06, (D) 0.02.

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

Genus 69. Cromyostaurus, Haeckel, 1881, Prodromus, p. 453.

Definition.—Staurosphærida with four concentric lattice-spheres and four crossed, equal, branched spines.

The genus Cromyostaurus differs from the preceding Staurocromyum, its ancestral form, in the ramification of the four crossed spines.

1. Cromyostaurus verticillatus, n. sp.

Radial proportion of the four spheres = 1 : 3 : 11 : 13. Both medullary shells with small, regular, circular pores; inner cortical shell with regular, hexagonal pores; from the hexagon-corners arise small, radial by-spines, which at equal distances from the centre send out forked tangential branches, three from each spine, and by communication of these form the outer, delicate, cortical shell. Four main spines nearly as long as the shell diameter, three-sided prismatic, with four to six verticils of ramified lateral branches, each verticil composed of three forked branches, which ramify again.

Dimensions.—Diameter of the four shells—(A) 0.26, (B) 0.22, (C) 0.06, (D) 0.02; length of the spines 0.24.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.