Dimensions.—Diameter of the shell 0.48; length of the spines 0.18.
Habitat.—Arctic Ocean (Greenland), in the contents of the stomach of the Peromedusa, Periphylla hyacinthina.
4. Porocapsa coronodon, n. sp.
Perspinal holes circular, with ciliated margin, which forms a crown of sixteen to twenty-four thin parallel teeth. Poruli of the shell surrounded by an elevated ring with high crenated margin. Four edges of the spines denticulate.
Dimensions.—Diameter of the shell 0.55; length of the spines 0.15.
Habitat.—Antarctic Ocean, Station 154, surface.
Genus 347. Cannocapsa,[[387]] 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 prolonged outside into radial tubes (each one in the radial ideal prolongation of one inner spine).
The genus Cannocapsa, exhibits the same peculiar reduction of the radial spines as the foregoing Porocapsa; the spines are also here shorter than the shell-radius and do not therefore reach the perspinal holes of the shell. But whilst these latter are simple in Porocapsa, they are prolonged into radial tubules in Cannocapsa; the outer surface bears therefore twenty such cylindrical tubules, separated by a short distance from the inner enclosed spines, but disposed quite regularly according to the law of Icosacantha.
1. Cannocapsa osculata, n. sp.