Habitat.—Central Pacific, Station 276, surface.
5. Drymosphæra dendrophora, n. sp. (Pl. [20], figs. 1, 1a, 1b).
Inner shell with irregular, polygonal meshes and very thin thread-like bars; outer shell one and a half times as broad, with simple triangular meshes and thicker bars, which bear a forest of very numerous, repeatedly dichotomous or irregularly branched, curved by-spines, longer than the diameter of the outer shell. Radial main spines with three dentated edges. All parts of the skeleton, the net bars as well as the radial beams and spines, are very elegantly denticulated (fig. 1b). The central capsule (fig. 1a) completely distends the inner shell and forces out protuberances through all its pores; in its centre lies a nucleus one-third its size.
Dimensions.—Diameter of the outer shell 0.25, inner 0.16.
Habitat.—Central Pacific, Station 271, surface.
Genus 100. Astrosphæra,[[135]] n. gen.
Definition.—Astrosphærida with two extracapsular cortical shells, connected by long, prismatic, radial spines; inner and outer shell with thin radial by-spines.
The genus Astrosphæra differs from its ancestral form, Leptosphæra, in the development of radial by-spines on the surface of both shells.
Subgenus 1. Astrosphærella, Haeckel.
Definition.—Radial main spines simple without lateral branches.