MILIOLIDAE - Acta Palaeontologica Polonica

102 EWA LUCZKOWSKA
forms, with a projecting middle chamber and depressed sutures are
regarded as belonging to S. mediterranensis (Bogdanowich). Nevertheless,
slender and convex forms without depressed sutures and distinct convex
middle chambers should be cosidered to be juvenile stages of Sigmoilopsis
foeda (Reuss).
Distribution. - Poland: Tortonian (Benczyn, Brzeznica, GliwiceStare,
Grabki Duze, Karsy, Krywald, Ligota Zabrska, L~ki Dolne, Niskowa, Wieliczka).
Czechoslovakia: Tortonian, Devinska Nova Ves, Zidlochovice.
USSR: Miocene, Tarkhan and Tchokrak of Crimea and Caucasus; Konka
of West- and East Precaucasian region; Lower Sarmatian of Transcarpathians.
Siphonaperta ovalis n.sp.
(PI. XIV, Fig. 4a-c; Text-fig. 34/3)
Holotypus: PI. XIV, Fig. 4.
Locus typicus: Niskowa near Nowy Sl\cz.
Stratum typicum: Upper Tortonian (Badenian) clays underlaying sands.
Derivatio nominis: ovalis (Lat.) - from the oval shape of the test.
Diagnosis. - Test regularly oval; surface evenly covered with fine sand
grains ·of nearly the same size.
Material. - 40 specimens (ColI. No. F-155, Sec. No. 416).
Dimensions: Holotype length 0.6 mm; breadth 0.35 mm; thickness
0.2 mm; Paratypes length 0.45-1.0 mm; breadth 0.3-0.55 mm; thickness
0.1-04 mm.
Description. - Test regularly oval, triangular with rounded edges in
cross-section, periphery broadly rounded; outer chambers arcuate, of uniform
width, with flattened sides, last chamber slightly extended downwards,
middle chamber convex, distinct, occupying about one-third of test
breadth, fifth chamber small but clearly visible; sutures distinct, slightly
depressed; wall calcareous, regularly covered with fine sand grains, which
are even with the surface; aperture circular, flush with the periphery or
at the end of the slightly extended last chamber, with a distinct lip and
a simple tooth slightly widened at the end.
Variability and ontogeny. The distinctive features of the species are
the constant regular shape of the test and the uniform type of wall
agglutination. The sections show a regular quinqueloculine arrangement
of chambers which gradually increase in size and are square-oval in crosssection.
The specimens sectioned belong to the micro generation, proloculus
diameter is 20 f.l (Text-fig. 34/3).
Remarks. - This species does not resemble any form known to the
author from literature and materials available.
Distribution. - Poland: Upper Tortonian (Niskowa).