Report on the Radiolaria Collected by H.M.S. Challenger During the Years 1873-1876, Second Part: Subclass Osculosa; Index / Report on the Scientific Results of the Voyage of H.M.S. Challenger During the Years 1873-76, Vol. XVIII

by Ernst Haeckel

2. Paratympanum octostylum, n. sp. (Pl. [94], fig. 14).

Eight divergent columellæ, about as long as the diameter of the octagonal mitral ring, connect it with the larger circular basal ring, and bear at each end a divergent, strong, conical spine. Lattice-plate of both rings slightly convex, with numerous subregular circular pores, smooth, without surface spines.

Dimensions.—Breadth of the mitral ring 0.06, of the basal ring 0.09.

Habitat.—Central Pacific, Station 268, depth 2900 fathoms.

3. Paratympanum decastylum, n. sp.

Ten divergent columellæ, only half as long as the diameter of the decagonal mitral ring, connect it with the larger circular basal ring. Lattice-plate of the mitral ring nearly hemispherical of the basal ring flat, both with numerous irregular roundish pores and scattered spines. Margin of both rings spiny.

Dimensions.—Breadth of the mitral ring 0.08, of the basal ring 0.1.

Habitat.—Central Pacific, Station 271, depth 2425 fathoms.

Genus 433. Lithotympanum,[^[52]] Haeckel, 1881, Prodromus, p. 447.

Definition.—Tympanida with two latticed horizontal rings, connected by numerous parallel and vertical columellæ; mitral and basal rings of equal size.