Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 50. (Budapest 1958)

M. Nyírő, R.: The studying of Foraminifera in thin sections

The apertures are to be traced along the separating walls, situated near the wall of the test too. The more elongated aperture of the last chamber is also well discernible. Number of chambers : 12—13. Nodogenerina badensis (d'Orb.) Plate figs. 7a-b Of a guttäte form ; the number of chambers few : 3—4. The chambers are regularly increasing, of a semicircular shape. The initial chamber shows a well-formed circular shape. The elongated, tubuliform aperture is recognizable in the inside of the test, at the separating walls of the chambers. The test is relatively thin. The elongated, tubuliform apertures of the chambers are well visible on the figures. Uvigerina pygmaea d'Orb. Plate figs. 9a-b-c-d Racemose, of a torsional structure, with a tubuliform aperture. The material of the test is calcite. I present two forms, one of them is the microspheric big form with a small initial chamber, with the ribbing absent on the last chamber. This ribbing is naturally invisible on the thin section picture ; the older chambers are very small, whilst the younger ones are suddenly inflated ; this feature gives the tapering to the uinmpaired specimen. The initial chamber of the macrospheric form is big, the form itself is small. The ribbing is absent also here on the young chamber. The number of chambers is much less in than that of the megalospheric form. Planulinella osnabrugensis (Miinst.) Plate figs. 13a-b Its initial chamber is circular. The younger chambers have a trapezoid form. The last two chambers are larger than the others. The test is thin, there is no perforation visible. There is a pearl-like ornamentiation on the external shell, visible also in a thin section. The separating walls describe an undulating line. The number of whorls is very small : 3—4. The number of chambers is, based on the section : 14—16. Well separable from the involuted forms discussed above. In thin sections, its chief characteristics is the wavy separating line of the walls. Cibicides ungerianus (d'Orb.) Plate figs. lOa-b The initial chamber is circular. The chambers are relatively small. The separating walls of the chambers thicken towards the external wall so that the chambers seem to be lobate. The last whorl is visible on the umbilical side.