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

3. Plagonium arborescens, n. sp.

Spines irregularly curved and branched, slender, cylindrical, thorny, twelve to sixteen times as long as the middle rod; the branches are large, arborescent, their ramules again ramified and very thorny.

Dimensions.—Length of the spines 0.2 to 0.25, of the middle rod 0.02.

Habitat.—Indian Ocean, Madagascar (Rabbe), surface.

4. Plagonium trigeminum, n. sp.

Spines straight, slender, cylindrical, four to six times as long as the middle rod, in the basal half smooth, in the distal half arborescent, with three to four irregular verticils of ramified branches. (Similar to a single spiculum of Sphærozoum verticillatum, Pl. [4], fig. 7.)

Dimensions.—Length of the spines 0.15 to 0.2, of the middle rod 0.05.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms.

5. Plagonium distriactis, n. sp.

Spines straight and stout, three-sided prismatic, smooth, ten to twelve times as long as the middle rod; each on the distal end cleft into three divergent straight branches, which are again trichotomous.