Page:Scientific results HMS Challenger vol 18 part 1.djvu/1005

Rh The Central Capsule of the Sphærocapsida is spherical, constantly smaller than the enclosing concentric shell, and separated from it by the calymma. Its structure seems to be the same as in the, and specially in the Astrolonchida. The pseudopodia (not yet observed) are probably protruded only through the twenty perspinal holes or the eighty aspinal pores.

Definition.—Radial spines connected with the porous shell, as long as or longer than its radius. Therefore the shell pierced by eighty aspinal pores (four around each spine).

Definition.— with twenty radial spines as long as the radius of the shell, without external prolongation; therefore their distal ends inserted in the perspinal holes, each of which is composed of four aspinal pores.

The genus Sphærocapsa is the most common form of the Sphærocapsida, and comprises those species in which the radial spines are as long as the radius of the shell, and therefore are connected with the margin of its aspinal holes, but not prolonged beyond its surface.