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

Subgenus 4. Discospira, Haeckel, 1862, Monogr. d. Radiol., p. 513.

Definition.—All rings of the disk spirally convoluted, forming parts of a simple or double spiral turning.

13. Porodiscus helicoides, Haeckel.

Discospira helicoides, Haeckel, 1862, Monogr. d. Radiol., p. 514, Taf. xxix. fig. 7.

Trematodiscus helicoides, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 841.

All rings of the disk spirally convoluted around the central chamber; spiral line regular, simple. All rings nearly of the same breadth, connected by numerous alternating radial beams. Chambers little different in size, little longer than broad. Pores of equal size, regular, two on the breadth of each ring.

Dimensions.—Diameter of the disk (with ten rings) 0.2; breadth of each ring 0.01; pores 0.0025.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific; also fossil in the Tertiary rocks of the Mediterranean, Sicily, Oran, &c.

14. Porodiscus spiralis, Haeckel.

Flustrella spiralis, Ehrenberg, 1840, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 210; Mikrogeol., 1854, Taf. xix. fig. 62.