Dimensions.—Diameter of the shell 0.16, of the parmal pores 0.015 to 0.02, of the sutural pores 0.003 to 0.004.
Habitat.—Tropical Atlantic, Station 349, surface.
6. Ceriaspis cicatricosa, n. sp.
Shell spherical, with two hundred and fifty to three hundred (or more) small funnel-shaped dimples, the majority of which are blind, the minority perforated by pores; of the latter forty are aspinal pores (two at the base of each spine), the others sutural pores. All pores nearly of the same size. As the shell of this species is very dark and thick-walled, it was impossible to obtain more information with regard to the pores. Radial spines very stout; the outer conical part shorter than the inner cylindrical part.
Dimensions.—Diameter of the shell 0.2, of the pores 0.006 to 0.008.
Habitat.—North Pacific, Station 236, surface.
Genus 355. Hystrichaspis,[[395]] n. gen.
Definition.—Dorataspida with twenty plates, which are perforated by forty aspinal pores (two pores in each plate). Surface of the shell with numerous dimples, separated by a network of elevated combs. Numerous by-spines.
The genus Hystrichaspis has the same structure with regard to the shell, as its ancestral form Ceriaspis, and differs from the latter only in possessing numerous by-spines. Moreover, in the former the dimples of the shell-surface are either all perforated by pores, or some of them are blind.