Report on the Radiolaria Collected by H.M.S. Challenger During the Years 1873-1876, First Part: Porulosa (Spumellaria and Acantharia) / Report on the Scientific Results of the Voyage of H.M.S. Challenger During the Years 1873-76, Vol. XVIII

by Ernst Haeckel

VIII. Monosphærida (with one single shell).

VIII. Dyosphærida (with two concentric shells).

VIII. Triosphærida (with three concentric shells).

IIIV. Tetrasphærida (with four concentric shells).

IIIV. Polysphærida (with five or more concentric shells).

IIVI. Spongosphærida (with spongy shells).

On the other hand, regarding the number of the radial spines and their regular disposition on the shell-surface, we can distinguish five families, viz.:—

VIII. Liosphærida (without radial spines).

VIII. Stylosphærida (with two radial spines, opposite in one axis).

VIII. Staurosphærida (with four radial spines, opposite in pairs in two axes, perpendicular one to another).