On the basis of an examination of the internal structure and aperture shape, the revision of some genera of Miliolidae is made. The genus Massilina is considered to be an ontogenetical stage of the genus Quinqueloculina. Five new genera are established: Cycloforina, Varidentella, Sinuloculina, Affinetrina and Crenatella. A new species, Crenatella mira, is described. Considering the quinqueloculine or kryptoquinqueloculine internal structure of particular genera, the emending of their diagnosis and subfamilies classification is proposed. The basic material to the presented study was derived from the Miocene of Poland and from Recent seas.
Descriptions are given of 103 species and subspecies of the Miliolidae from the Miocene of Poland, including 9 new species and 1 new name. A new genus, Articularia, and a new subfamily, Sigmoilinitinae, comprising species which show a sigmoiline initial stage and not a quinqueloculine or cryptoquinqueloculine one, have also been separated. The distribution and stratigraphic range of the species under study in the Tortonian and Sarmatian of Poland have been discussed and the hypothetical palaeoecologic conditions prevailing in the coastal facies of the Miocene sea reconstructed.