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

Rings of the skeleton elliptical, smooth or slightly denticulate on the outer margin, without spines. This species is possibly identical with Mesocena crenulata of Ehrenberg, of which, however, no figure is given. The major axis of the ellipse is one and a half times as long as the minor.

Dimensions.—Diameter of the rings in the major axis 0.03, in the minor 0.02; thickness of the bars 0.002.

Habitat.—Tropical Atlantic, Station 347, depth 2250 fathoms.

3. Mesocena diodon, Ehrenberg.

Mesocena diodon, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 84.

Mesocena diodon, Ehrenberg, 1854, Mikrogeol., Taf. xxxiii., Nr. xv. fig. 18.

Rings of the skeleton elliptical, smooth, with two opposite spines on the poles of the major axis, which is about one and one-third as long as the minor axis.

Dimensions.—Diameter of the rings in the major axis 0.04, in the minor 0.03; length of the spines 0.01.

Habitat.—Fossil in Barbados, and in North America (Virginia).

4. Mesocena triangula, Ehrenberg.