MILIOLIDAE - Acta Palaeontologica Polonica

130 EWA I:.UCZKOWSKA
figured by Reuss from Baden, are however rather oval, not quadrangular
in shape. This being the only difference and at that probably representing
geographical variation, the specimen was identified as S. microdon. Our
adult specimens are somewhat similar to Miliolina collaris Gerke & Issaeva,
differ however in their broader and more massive chambers, in the
lack of a narrow extension of the last chamber, and in the tendency to
have a wrinkled periphery.
Distribution. - Poland: Tortonian (Bogoria, Bogucice, Gliwice Stare,
Karsy). Austria: Tortonian, Baden, Voslau, Vienna Basin. Czechoslovakia:
Lower Tortonian, Zidlochovice.
Sinuloculina nitens (Reuss, 1850)
(pI. XXV, Figs la-c, 2; Text-fig. 43/2--4)
1850. Triloculina nitens Reuss; A. E. Reuss, p. 383, PI. 49, Fig. lOa-d.
1970. Triloculina nitens Reuss; V. J. Didkovsky & Z. N. Satanovskaja, p. 59, PI. 36,
Fig. 4.
Material. - About 100 specimens (ColI. No. F-182, Sec. No. 179-181).
Dimensions: L 0.8-0.9; B 0.3; T about 0.2.
Description. - Test very narrow and elongate, nearly quadrangular in
shape, sometimes with a slight extension of the last chamber, depressed,
periphery rounded; chambers narrow, somewhat expanded at the base and
near the aperture, middle chamber narrow and long, a little convex, fifth
chamber often occurs as a narrow tape; 3-5 chambers visible from
outside; sutures sligthly depressed, distinct; wall thin; surface smooth,
polished; aperture circular, small, even with the periphery or at the end
of a slight extension of the chamber, and with a short bifid tooth.
Variability. The length/width ratio of the test is variable, and so are
the degree of the roundedness of chambers at the base and the apertural
extension of the last chamber. There occur specimens whose a.pertural
end is nearly horizontally truncate, the last chamber being even with the
periphery, and others with the last chamber extended to form a small
constricted neck. The test of forms with the projecting apertural end
narrows at both ends (Text-fig. 43/2), whereas forms which lack a neck
are rounded at the base and truncate at the end and resemble Sinuloculina
consobrina (d'Orbigny) (Text-fig. 43/4). The number of chambers visible
from outside oscillates between three and five.
Dimorphism and ontogeny. The internal structure of juvenile stage is
quinqueloculine, becoming irregularly quinqueloculine or cryptoquinqueloculine
in the· adult stage. The specimens sectioned belong to the ·micro
generation with the proloculus 30--40 p. in diameter. The chambers are
semicircular in cross-section throughout the ontogeny.
Remarks. - This species, described from Grinzing in Austria, morphologically
resembles Sinuloculina consobrina (d'Orbigny) from Nussdorf in,