MILIOLIDAE - Acta Palaeontologica Polonica

MILIOLIDAE FROM MIOCENE OF POLAND 127
The juvenile stage obtained from the inside of an adult specimen does not
differ morphologically from it, being only of much smaller proportions.
Remarks. - Our specimens correspond to the comparative specimens
from Voslau and Buitur, only that they are slenderer in shape. From
Triloculina gubkini (Bogdanowich) they differ in the broadly rounded, not
flattened periphery and in the oval, not triangular outline in cross-section:
they are however very close to each other. Morphologically they resemble
Sinuloculina mayeriana (d'Orbigny), but differ in havjng a considerably
thicker massive test and specifically inflated and expanded lower parts
of chambers.
Distribution. - Poland: Tortonian (Bogoria, Grabowiec, Niskowa, Rybnica,
W~glinek, Wieliczka). Austria: Tortonian, Nussdorf, Voslau, Vienna
Basin. Italia: Pliocene, Castell' Arquato. Romania: Tortonian, Buitur,
USSR: Upper Tortonian, the Volhyn-Podolian Platform, the Precarpathian
Foredeep, Blak Sea Depression; Meotian (Pliocene) the South
Ukraine. Recent: Mediterranean Sea.
+ Sinuloculina mayeriana (d'Orbigny, 1846)
(PI. xxv, Fig. 8a-c; Text-fig. 42)
1846. QuinquelocuZina mayeriana d'Orbigny; A. d'Orbigny, p. 287, PI. 18, Figs 1-3.
Material. - About 100 specimens (ColI. No. F-180, Sec. No. 116-120).
Dimensions: L 1.0-1.45; B 0.5-0.9; T. 0.3-0.5.
Description. - Test quadrangular-oval or elongate, flattened; periphery
rounded; chambers flat, broad, somewhat broader at the base, last
chamber straighened or bent towards the aperture, third chamber slightly
convex or flat, narrow and elongated; usually three or rarely two
chambers visible from outside; sutures flat, distinct, with a fairly broad,
faintly marked border along the chamber edges; wall thin; surface smooth,
usually matt; aperture circular, rimless, with a sinuous border and a large
tooth bifid at the end, and often protruding above the aperture edge.
Variability. The test shape is variable, being sometimes more flattened,
with a tendency to the S-shaped bending of the last chamber.
Dimorphism and ontogeny. All specimens sectioned belong to the
micro? generation, having a PD 50-70 f.l. The internal structure is cryptoquinqueloculine
initially, then biloculine, the opposite chambers being
arranged in a sinusoid line (Text-fig. 42). The chamber outline is unchangeably
semicircular in cross-section. The juvenile specimens removed from
the inside of adults do not differ from them in shape.
Remarks. - This species differs from Sinuloculina microdon (Reuss)
in the more oval and less elongate test shape, more flattened sides, and
less depressed sutures. From S. rixatoria (Franzenau) it differs in the less
inflated quadrangular-oval test shape, the lack of the thickened rim round