Subfamily Staurocaryida, Haeckel, 1881, Prodromus, pp. 449, 454

Definition.—Staurosphærida with five or more concentric spherical lattice-shells.

Genus 70. Staurocaryum, Haeckel, 1881, Prodromus, p. 454.

Definition.—Staurosphærida with five or more concentric lattice-spheres and four crossed, equal spines.

The genus Staurocaryum has arisen from the preceding Staurocromyum by the further multiplication of the concentric spheres; in the only observed form there are six, at nearly equal distances apart.

1. Staurocaryum arborescens, n. sp. (Pl. , fig. 8).

Shell composed of six concentric latticed spheres, at nearly equal distances apart, and with somewhat regular, circular pores, the size of which gradually increases from the first to the sixth shell. The surface of the outermost shell is densely covered with numerous arborescent by-spines, which bifurcate from three to four times, and are three-sided pyramidal at the base, and twice as long as the distance between each two shells. The six shells are connected only by four crossed, conical, radial beams, which increase in diameter from the centre, and are prolonged outside into very stout cylindrical, radial spines, irregularly covered with small thorns and forked ramules, and nearly as long as the shell diameter. Only a single specimen was observed.

Dimensions.—Diameter of the whole shell 0.22; distance between each two shells 0.02; length of the by-spines 0.05, of the main spines 0.2.

Habitat.—Indian Ocean, Cocos Islands, surface, Rabbe.