MILIOLIDAE - Acta Palaeontologica Polonica

MILIOLIDAE FROM MIOCENE OF POLAND 81
Variability. The test shape ranges from narrowly oval to broadly oval,
the aperture may be flush with the surface or placed at the end of a short
neck (Text-fig. 30). The ornamentation varies from simple longitudinal
ribs running along the whole chamber to bifurcated, interrupted or undulate
ones. The shape of the tooth is also variable and may be broad and
quadrate in specimens without the neck, or short and nllrrow in those
with it.
Dimorphism and ontogeny. The specimens sectioned belong to the
micro generation, PD 30 fl. The chamber shape in cross-sections is constant
(Text-fig. 29/3), and does not change during ontogeny.
Remarks. - The specimens of Cycloforina karreri ovata investigated
Fig. 29. Internal structure of Cycloforina indicated by cross-sections. 1 - C. reticulata
(Karrer), Lower Tortonian, Korytnica, mega I generation; 2 - C. toreuma (Serova),
Lower Sarmatian, Zrecze-3 borehole, depth 64.8-64.9 m, micro generation; 3 - C. karreri
ovata (Serova), Lower Sarmatian, Mach6w 250 borehole, depth 84.3-85.3 m, micro
generation.
I lmm
totl ~Jt t t),o '0
I.olofll
120
130 140
~b~b~Ob~~ ~ ~
llb 12b 13b 14b
Fig. 30. Morphological variability of Cycloforina karreri ovata, Lower Sarmatian,
Zrecze-3 borehole, depth 11 m; 1-7 - ovate specimens with typical ornamentation
and with aperture on the prolongation of the chamber; 8-14 - broadly ovate specimens
with irregular ornamentation and with the aperture without prolongation;
a front view, b apertural view.
6 Acta Palaeontologica nr 1/74