Habitat.—North Pacific, Station 241, surface.
4. Astrocapsa coronata, n. sp. (Pl. [133], fig. 9).
Aspinal holes circular, with a coronet of numerous thin parallel teeth. Porules of the shell in dimples on irregular polygonal small plates, with coronated ring. Four edges of the spines denticulate; their outer free part about twice as long as the diameter of the shell.
Dimensions.—Diameter of the shell 0.4 to 0.5 ; outer length of the spines 1.0 to 1.2.
Habitat.—North Atlantic, Færöe Channel, Gulf Stream (expedition of the "Knight Errant," 1880), John Murray, surface and at depths varying from 10 to 200 fathoms.
Subfamily 2. Porocapsida, Haeckel.
Definition.—Radial spines not connected with the porous shell, shorter than its radius; therefore the shell pierced by twenty perspinal pores (each one in the ideal radial prolongation of one spine).
Genus 346. Porocapsa,[[386]] n. gen.
Definition.—Sphærocapsida with twenty radial spines shorter than the radius of the shell; therefore their distal ends not connected with the twenty perspinal holes, which are simple, not prolonged into radial tubes.
The genus Porocapsa and the following Cannocapsa form together the small sub-family of Porocapsida, distinguished by the peculiar reduction or retrograde development of the twenty radial spines; all these twenty are present and disposed according to the Müllerian law of the Icosacantha, but they are shorter than the radius of the shell and therefore do not reach it. In the ideal prolongation of the spines the shell is pierced by twenty simple quadrangular or circular perspinal holes.