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 1. Amphirrhopalium, Haeckel.

Definition.—Both opposite arms of similar size and form, with blunt branches, without terminal spines.

1. Amphirrhopalum ximorphum, n. sp.

Both arms equal, in the proximal half simple, in the distal half forked, with six to seven transverse septa; distal end of each branch blunt, without terminal spine, somewhat broader than the base of the whole arm. Axis of the branches concavely curved. (Resembles Amphicraspedum maclaganium, Pl. [45], fig. 11, but wants the patagium.)

Dimensions.—Radius of the arms 0.18, basal breadth 0.065; terminal breadth of each branch 0.075.

Habitat.—North Pacific, off Japan, Station 240, surface.

2. Amphirrhopalum amphidicranum, n. sp.

Both arms equal, in the proximal half simple, in the distal half forked, with irregular septa; distal end of each arm blunt, without a terminal spine, smaller than the basal breadth of the arm. Axis of the branches straight. (Resembles Dicranastrum furcatum, Pl. [47], fig. 2, but without lateral arms.)

Dimensions.—Radius of each arm 0.15, basal breadth 0.03; terminal breadth of each branch 0.02.

Habitat.—Pacific, central area, Station 263, depth 2650 fathoms.