Geinitzina is a genus of Foraminifera (ProtistaSen Gupta, 1999. Modern Foraminifera or ProtozoaForaminiferida: Kingdom Protozoa. GBIF data portal as of 9Mar2013.) from the early Carboniferous (late Mississippian to the late Permian that may have extended into the Triassic. Chambers are uniserial, arranged in a single row, or line. Test wall is double layered. The outer layer is of hyaline radial calcite, and is light in color. The inner layer is of microgranular calcite, and is dark is color. Both layers are secreted by the protoplasm.
Geinitzina is included in the Fusulinida (Loeblich & Tappan, 1984, 1988) on the basis of test wall composition, in having a secreted microgranular layer.
References
Further reading A. R. Loeblich and H. Tappan. 1984. Suprageneric classification of the Foraminiferida (Protozoa). Micropaleontology 30(1):1–70 __ __ 1988.* Forminiferal Genera and their Classification. E-book Geinitzina in The Paleobiology Database.