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

Spines spindle-shaped, tapering from the thicker central part towards the two thin conical ends, rigid, inelastic; their central part is spirally convoluted in a very peculiar cochlea-like manner, as in Chiastolus amphicopium (Pl. [129], figs. 3a, 3b). The ten spines are propped one upon another by the central screw. Central capsule dark, opaque.

Dimensions.—Length of the spines 0.2 to 0.3, breadth of the central spiral part 0.01.

Habitat.—Central Pacific, Station 266, surface.

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Suborder II. ACANTHONIDA, Haeckel (Pls. [130]-[132]).

Acanthonida, Haeckel, 1881, Prodromus, p. 465.

Definition.—Acanthometra with twenty radial spines, disposed according to the Müllerian or Icosacanthan law in five zones each of four spines.

Family XXXVI. Astrolonchida, Haeckel (Pl. [130]).

Astrolonchida, Haeckel, 1881, Prodromus, p. 465.

Definition.—Acanthometra with twenty radial spines of nearly equal size and similar form, disposed according to the law of the Icosacantha. No lattice-shell.