Parmal meshes of different size and form; in the centre of each plate a cross of four pentagonal, primary aspinal pores, surrounded by a complete corona of twelve to sixteen polygonal coronal pores and an incomplete corona of thirty to forty very small marginal pores; the latter are not to be distinguished from the pores of the obliterated sutures. Radial spines quadrangular, the outer pyramidal part shorter than the inner prismatic part. Condyles grown together. As the plates are quite even, the shell becomes icosahedral.
Dimensions.—Diameter of the shell 0.16, pores 0.002 to 0.02, bars 0.005.
Habitat.—North Pacific, Station 241, surface.
9. Icosaspis icosastaura, n. sp. (Pl. [136], fig. 3).
Tessaraspis icosastaura, Haeckel, 1882, Manuscript et Atlas.
Parmal plates of different size and form; in the centre of each plate a cross of four larger primary, pyriform aspinal pores; between these four smaller roundish angular pores, and around this rosette a circle of ten to twenty (commonly sixteen) coronal pores, little larger than the very small sutural pores. Radial spines very thin and long, cylindrical or bristle-shaped. Condyles grown together; no suture visible.
Dimensions.—Diameter of the shell 0.14; larger pores of the cross 0.01, smaller pores 0.002 to 0.008; bars 0.002 to 0.004.
Habitat.—Central Pacific, Station 268, surface.
Genus 365. Hylaspis,[[405]] n. gen.
Definition.—Dorataspida with twenty plates, which are perforated by one hundred and sixty to three hundred or more parmal pores (in each plate four crossed aspinal pores, and around them four to twelve or more coronal pores). Surface covered with numerous by-spines.