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.
Subfamily Staurocaryida,[[96]] Haeckel, 1881, Prodromus, pp. 449, 454.
Definition.—Staurosphærida with five or more concentric spherical lattice-shells.
Genus 70. Staurocaryum,[[97]] Haeckel, 1881, Prodromus, p. 454.
Definition.—Staurosphærida with five or more concentric lattice-spheres and four crossed, equal spines.