Genus 122. Cenellipsis,[[161]] n. gen.
Definition.—Ellipsida with simple ellipsoidal shell, without radial spines and without polar tubes.
The genus Cenellipsis is the simplest and most primitive form, not only among the Ellipsida, but also among the Prunoidea, and it may therefore be regarded as the common ancestral form of the whole family. It corresponds to Cenosphæra among the Sphæroidea, to Cenodiscus among the Discoidea, to Cenolarcus among the Larcoidea. Probably it is derived from Cenosphæra by prolongation of one axis.
Subgenus 1. Cenellipsium, Haeckel.
Definition.—Network of the shell regular, with meshes of equal size and similar form.
1. Cenellipsis primitiva, n. sp.
Proportion of the longer axis of the ellipsoid to the shorter = 3 : 2. Network of the thin wall very delicate and regular, with hexagonal pores. All pores of nearly the same size and form, ten to twelve times as broad as the bars; nine to twelve on the half equator of the shell. Surface smooth.
Dimensions.—Longer axis of the ellipsoid 0.09 to 0.11, shorter axis 0.06 to 0.08; pores 0.01, bars between them 0.001.
Habitat.—Pacific, central area, Station 272, surface.
2. Cenellipsis faceta, n. sp. (Pl. [39], fig. 1).