MILIOLIDAE - Acta Palaeontologica Polonica

142 EWA LUCZKOWSKA
tooth varies from slight ridge-like swelling at the base of· the aperture
to low transverse tape. There occur longitudinal irregular wrinkles,
like in Cyclojorina predcarpatica (Serova), in some specimens (Part I,
PI. XIII, Fig. 2) probably representing gerontic stage of the species.
lmm
(1:1®3{~
-/'-.-//k ~,~,~,
Fig. 48. Morphological variability and internal structure of VaridenteHa reussi (Bogdanowich),
Lower Sarmatian, Miechocin 0-3 borehole, depth 54.6-55.7 m, rounded
forms: I-micro generation with initial part irregular, then quinqueloculine; 2­
micro generation, initial part with turn of coiling axis, later quinqueloculine;
3 - micro generation, initial part cryptoquinqueloculine, then quinqueloculine; 4­
mega I generation with irregularly quinqueloculine internal structure; a front view,
b apertural view, c cross-section.
Dimorphism and ontogeny. The specimens sectioned belong to the
micro generation, PD 20-40 ~l (Text-figs 48/1-3, 49/1-4) and to the
mega I generation, PD 70 Il (Text-fig. 48/4). The internal structure is
quinqueloculine or cryptoquinqueloculine. The juvenile stage of the micro
generation is composed of about 7 chambers in a quinqueloculine arrangement,
then the coiling axis turns by about 90 0 and the subsequent 2-3
chambers grow nearly perpendicularly to the main axis; finally the coiling
axis may return to the previous direction and the mature specimens may
have a quinqueloculine appearance. The juvenile specimens with transparent
walls show a distinct oblique position of the middle chambers after
the coiling axis has been changed (Part I, PI. XIII, Fig. 3).
Remarks. - This species differs from Varidentella sarmatica (Reuss)
in its more compact, broadly oval or nearly circular shape of the test, low
and broad aperture with tape-like tooth and dull, often wrinkled surface.
From Cyclojorina stomata sp. n. it differs in slitlike, not circular aperture