MILIOLIDAE - Acta Palaeontologica Polonica

MILIOLIDAE FROM MIOCENE OF POLAND 101
and are almost round in cross-section. The specimens sectioned belong to
the mega I (?) generation; PD 70 I.l (Text-fig. 34/2).
.Remarks. - This species differs from Sigmoilina rustica Bermudez
from the Middle Miocene of the Dominican Republic in more elongated
and lower test.
Distribution. - Poland: Upper Tortonian (Gliwice Stare, Ligota Zabrska).
* Siphonaperta mediterranensis (Bogdanowich, 1950)
(pI. XIV, Figs. 7a, b, 8a, b; Text-fig. 34/4)
1950b. Sigmoilina mediterranensis Bogdanowich; A. K. Bogdanowich, p. 160, PI. 6,
Fig. 2a-c.
1952. Sigmoilina mediterranensis Bogdanowich; A. K. Bogdanowich, p. 165, PI. 24,
Fig. 3.
1958. Sigmoilina mediterranensis Bogdanowich; I. V. Venglinsky, p. 87, PI. 17,
Fig la-c.
1959. Sigmoilina mediterranensis Bogdanowich; V. A. Krasheninnikov, p. 86, Pl. 2,
Fig. 3.
Material. - 50 specimens (ColI. No. F-154, Sec. No. 415).
Dimensions: L 0.7-1.2; B 0.35-0.55; T 0.25-0.4.
Description. - Test narrowly oval or quadrangularly oval, periphery
broadly rounded; outer chambers thick, tubular, basically curved and
usually straight at the top, middle chamber large, tubular, convex, fifth
chamber poorly visible or invisible; sutures depressed, indistinct; wall
calcareous, roughened by a thin coating of fine sand grains; aperture
round, at the end of an only slightly developed neck, with a definite lip
and a short simple tooth.
Variability and ontogeny. The test shape is variable, as the last
chamber may be arcuate or straight at the apertural end. The thickness
of the test and the length of the extension of the last chamber are also
variable, being more or less well-developed. The section shows the
irregular quinqueloculine internal structure. The specimen sectioned
represents the mega I (?) generation; PD 70 f.l (Text-fig. 34/4).
Remarks. - The autor of the species figured a specimen, the test
morphology of which resembles our specimens; it has a prominent middle
chamber and a narrowly oval test. However, he mentioned in the description
that the species includes also flat forms, broadly oval in shape and
with the spiroloculine arrangement of chambers in the mature stage. In
our materials from coeval beds both forms described by Bogdanowich
occur together. As Bogdanowich does not illustrate the flattened forms,
and our analogical flat forms from the Miocene of Wieliczka have been
identified as Sigmoilopsis foeda (Reuss), it is supposed that Bogdanowich's
flat forms also belong to this last species, The slender quinqueloculine