Subfamily Xiphostylida, Haeckel, 1881, Prodromus, pp. 449, 450.
Definition.—Stylosphærida with one simple spherical lattice-shell.
Genus 45. Xiphosphæra,[[68]] Haeckel, 1881, Prodromus, p. 450.
Definition.—Stylosphærida with one single lattice-sphere and two free spines of equal size and form.
The genus Xiphosphæra is the most simple form of all Stylosphærida, and may be regarded as the common ancestral form of this family. On the surface of a simple spherical lattice-shell, enclosing the central capsule, arise two equal, free, radial spines, opposite to each other on the poles of one axis.
Subgenus 1. Xiphosphærantha, Haeckel.
Definition.—Pores of the spherical shell regular, of nearly equal size and form; surface smooth or a little rough, without spines or thorns (other than the two polar spines).
1. Xiphosphæra planeta, n. sp.
Pores regular, hexagonal, eight to nine times as broad as the thin bars. Ten to twelve pores on the half equator. Shell very thin walled; surface smooth. Polar spines three-sided pyramidal, about as long as the axis of the sphere, as broad at the base as one pore.
Dimensions.—Diameter of the sphere 0.12 to 0.13, pores 0.016 to 0.018, bars 0.002; length of the polar spines 0.1 to 0.15, basal thickness 0.02.