Plate 2, fig. 1. Austrotrillina ? sp. Large, microspheric specimen with an enormously thickened basal layer and a doubtful alveolar exoskeleton in the final uncoiled chamber. Oblique section; figs. 2-9. Austrotrillina eocaenica n. sp. 2: oblique, almost centered section perpendicular to the apertural axis. Center recrystallized. Note alcoves below the suture of the chamber. In addition, on the upper left, an axial section of the conical nepiont of Neotaberina neaniconica n. gen. n. sp. and on the lower left a part of an oblique section of Archaias operculiniformis Henson, 1950. 3: Top: section of a megalospheric specimen perpendicular to apertural axis tangentially cutting the proloculus. Bottom: microspheric specimen, section in the apertural axis. Note the triangular foramen with a pointed tooth. 4: holotype. Oblique centered section. Note alcoves below the chamber suture. 5: tangential section. Note thickness of basal layer. 6: oblique centered section showing part of long flexostyle. 7: section pependicular to apertural axis. In addition to the left, oblique section of Archaias operculiniformis Henson, 1950. 8: section parallel to and near the apertural axis. In addition, on bottom right, an axial section of a juvenile specimen of Neotaberina neaniconica n. gen. n. sp. 9: section perpendicular to apertural axis; figs. 10-12. "Peneroplis" dusenburyi Henson, 1950. 11-12: axial sections, more or less well centered. 12: oblique and equatorial sections.
Abbreviations: alc: alcoves; alv: alveoli; bl: basal layer; f: foramen; t: tooth; s: septum.