MILIOLIDAE - Acta Palaeontologica Polonica

44 EWA LUCZKOWSKA
Description. - QS rhomboid with subacute periphery, subtriangular in
cross-section; chambers slightly inflated, arcuate, central chamber small,
convex, rhomboid in shape, with distinct roundish-angular edge, fifth
chamber poorly visible or lacking; MS rhomboid-rounded, with subacute
periphery, lenticular in cross-section; chambers broad, slightly inflated,
two middle chambers small, flat; sutures flush and indistinct; surface
smooth and dull; wall thick; aperture oval with simple tooth, slightly
broadened at the end.
Variability. A remarkable and constant character of the species is the
rhomboid shape of the test. The convexity of chambers is unstable and
the outline of the periphery varies from subacute to acute.
lmm
~®
3b 4b
~e
2c 3c 4c
Fig. 10. Ontogeny and dimorphism of Quinque[ocu[ina bogdanowiczi (Serova), Upper
Tortonian, W~glinek; 1 - MS, micro generation; 2 - QS, micro generation; 3,4- QS,
mega I generation; a front view, b apertural view, c cross-section.
Dimorphism. Micro and mega I generations are observed in .crosssections
but are not conspicuous in the test morphology (Text-fig. 10).
PD: micro 20-30 ~, mega I 100 l!-l.
Remarks. - From Quinqueloculina triangularis d'Orbigny it differs
in the rhomboid shape and smaller thickness of the test and in its
thicker wall.