Habitat.—Western Tropical Pacific, Station 206, depth 2100 fathoms.
Genus 483. Perispyris,[[101]] Haeckel, 1881, Prodromus, p. 444.
Definition.—Androspyrida without free basal feet, with three distinct joints, separated by two transverse strictures; lattice-work of the shell double or spongy.
The genus Perispyris differs from the preceding Tricolospyris, its ancestral form, in the development of a secondary outer shell, which encloses the inner primary one either like an enveloping cortical shell or like a spongy veil. This is produced by the concrescence of meeting branches, which arise from spines of the inner shell.
1. Perispyris bicincta, n. sp. (Pl. [88], fig. 13).
Shell smooth, with two deep transverse annular strictures and a deep sagittal incision at the sternal base; one and a half times as long as broad. Cephalis nut-shaped, with large irregular roundish pores and very broad bars. Everywhere from its surface there arise numerous slender arborescent radial beams; by the anastomoses of their ramified branches there arise the flat cap-shaped cupola and the larger bilobed thorax; and also the external enveloping shell with loose delicate network.
Dimensions.—Inner shell 0.17 long, 0.1 broad; outer shell 0.23 long, 0.17 broad; ring 0.06 long.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
2. Perispyris spongiosa, n. sp.
Shell rough, with two distinct transverse strictures and a deep sternal incision, similar to the preceding; the radial beams arising from the inner shell, and forming by anastomosing branches the outer shell, are thinner and more numerous, and the framework of the latter on the surface is very dense and spongy, therefore the shell is dark and not transparent.