Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 75. (Budapest 1983)

Szabó, J.: Lower and Middle Jurassic Gastropods from the Bakony Mountains (Hungary). Part V.: Supplement to Archaeogastropoda; Caenogastropoda

Remarks — The spiral striation of the Bakony specimens are somewhat stronger and the number of the basal spiral lines is lower than on the figures of UHLIG. Lamelliphorus? sp. (Plate I: fig. 13) Measurements: H HL HA D W A Plate I: fig. 13. — 14 10 16 11 — Material — A single damaged specimen with shell. Shape — Dextral form with slightly coeloconoid spire and slightly convex whorls; the periphery is sharp and the base is hardly convex. Ornament — The whorls and the base are covered by spiral cords. The run of the growth lines is strongly prosocline — slightly prosocyrt on the whorls and strongly prosocline — slightly opisthocyrt on the base. Distribution — Bakony Mts, Sümeg: ?Upper Sinemurian. Remarks — The structure of the peristome seems special. The coiling of the last whorl neat the aperture deviates from that of the other parts of the shell, i. e. the periphery continues from a point tangentially, while the suture follows the previous direction. The aperture, which is suddenly expanded in this way, is restricted by a constriction on the basal lip. Because of the imperfect preservation, it cannot be ascertained what caused this shell and peristome shape. Similarly uncertain is the presence or absence of an umbilicus. The shell form and the sculpture of the shell are close to those of Lamelliphorus species, but the special shell-building around the aperture is different. Further material is needed to clear the exact systematic position. Superfamily Cerithiacea FLEMING, 1822 Family Proeerithidae COSSMANN, 1905 Genus CERITHINELLA GEMMELLARO, 1878 Cerithinella rigauxoides sp. n. (Plate II: figs 8-9) H o 1 o t y p u s : Plate II, fig. 9. — Locus t y p i c u s : Bakonybél, Somhegy. — Stratum t y p i c u m : limestone infilling horizontal fissure. — Derivatio nominis: the juvenile shell perfectly matches the description of genus Rigauxia COSSMANN, 1885. Diagnosis : extremely high spire with great number of whorls : spiral grooves and lines on the whole shell; subsutural tuberculate spiral convexity on the juvenile shell, the tubercles disappear then reappear strengtheningly on the adult shell; suprasutural row of tubercles from the middle of the shell-part characterized by the lack of the other tuberculate row. Measurements: H HL HA D W A Plate II: fig. 9. — 12.5 — 5.8 3 7.5° Material — A single, well-preserved shelly specimen. Shape — Dextral shell with very high spire. The surface of the juvenile whorls is sigmoidal, and there are convexities below and above the suture of the adult shell. Between the two convex zones the surface is slightly concave. The suture runs in a groove. The internal space of the whorls is paralelogram-shaped in section, with smooth walls. The base is slightly convex, without umbilicus. Only the strongly thickened inner lip of the peristome can be studied ; it is reflected to leave free only a narrow outer zone of the base. Ornament — The many-whorled shell bears an ornament varied by different growth stages. The juvenile shell (i.e. the first preserved 13 whorls) is covered by initially rare, then denser fine spiral furrows, and the subsutural convexity bears a row of small nodes which disappear on the 10th whorl. After the next three whorls, suddenly starting rather strong tubercles appear suprasuturally, forming a row with a weak connecting carina and this continues up to the aperture. With the appearance of the lower row of tubercles the width of the spiral furrows increase and fine spiral lines appear between them. In the place of the juvenile nodose row, 3 to 4 whorls after the appearance of the suprasutural