Cyrtocalpis obliqua, Haeckel, 1862, Monogr. d. Radiol., p. 286, Taf. v. figs. 4-11.
Shell smooth, irregularly ovate, more or less oblique, variable in size and form, sometimes nearly spherical, at other times subcylindrical. Pores subregular, circular, once or twice the breadth of the bars. Mouth simple without peristome, about half as broad as the shell.
Dimensions.—Shell 0.07 to 0.1 long, 0.05 to 0.08 broad; mouth 0.03 to 0.04 broad.
Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.
10. Cyrtocalpis gromia, n. sp. (Pl. [51], fig. 11).
Shell rough, ovate, very thick-walled, with subregular, circular pores of somewhat variable size. The diameter of the internal, simple, subspherical cavity is five to six times as great as the thickness of the wall. Mouth tubular, cylindrical, very narrow, only one-sixth as broad as the shell.
Dimensions.—Shell 0.16 long, 0.11 broad; mouth 0.02 broad.
Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.
Genus 530. Mitrocalpis,[[147]] Haeckel, 1881, Prodromus, p. 427.
Definition.—Archicorida with a double ovate or ellipsoidal shell, composed of two parallel lattice-plates, which are connected by numerous beams. Apex without horn.