Figure 82: Trematophores.
A: stereograph of the trematophore of Lacazinella supported by a single residual pillar in axial position. Schema, not to scale. B-F: Lacazinella wichmanni (Schlumberger) from the Vogelkop, New Guinea. Middle-Upper Eocene. Transmitted light micrographs. All specimens are megalospheric. B: sections tangential to a septal face. C: a section perpendicular to the apertural axis reveals the concentric growth of the chambers from their beginning. D: section in the apertural axis. Note the alternation of the trematophore on opposite poles of the shell in successive chambers. E: oblique section cutting the apertural axis in a pillar supporting the trematophore. F: oblique section not cutting the apertural axis within the shell. Note the interruption of the septula below the equatorial roof of the chambers.
a: aperture; af: apertural face; apax: apertural axis; bl: basal layer; f: foramen; pi: pillar; psp: preseptal space; s: septum by transformation of the outer chamber wall that is totally covered by a new concentric chamber; sf: septal face; sl: septulum.