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

Discospira bilix, Stöhr, 1880, Palæontogr., vol. xxvi. p. 113, Taf. vi. fig. 3.

All rings of the disk spirally convoluted around the large elliptical central chamber. Spiral convolutions of the inner rings simple, of the outer rings double; the latter twice as broad as the former. Pores regular, circular, in the inner rings one pore on the breadth, in the outer rings two to three pores. Radial beams piercing, numerous, on the margin prominent.

Dimensions.—Diameter of the disk (with six rings) 0.14; breadth of the inner rings 0.007, of the outer 0.013; pores 0.0017.

Habitat.—Fossil in the Tertiary rocks of Sicily, Grotte, Stöhr.

17. Porodiscus bispiralis, Haeckel.

Stylodictya bispiralis, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 160. Taf. xxiv. fig. 1.

All rings of the disk spirally convoluted, in a perfect double spiral, with increasing breadth of the rings; the fourth ring twice as broad as the first. Pores regular, circular; in the inner rings one pore on the breadth, in the outer rings two to three pores. Radial beams piercing, numerous, prominent on the margin.

Dimensions.—Diameter of the disk (with four rings) 0.1; breadth of the inner rings 0.006, of the outer 0.012; pores 0.0015.

Habitat.—Fossil in the rocks of Barbados; living in the depths of the Central Pacific, Station 268, depth 2900 fathoms.

18. Porodiscus duplex, Haeckel.