Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 15. 1992. (Budapest, 1992)

species without description. P pseudopotyptycha is similar to P potyptycha which is, however, larger and its valves form a less acute angle at the anterior commissure. According to Vígh (1943), the number of costae can increase by bifurcation or intercalation. On the material of Lókút Hill this is not common. Distribution: According to Aimeras (1964), P. pseudopotyptycha is Sinemurian in age. Vörös (1982) documented that it ranges up to the Ibex Zone of the Early Pliensbachian in the Bakony Mountains. The species was reported from the Gerecse Mountains and the Bakony Mountains. Family RHYNCHONELLIDAE GRAY, 1848 Subfamily TETRARHYNCHIINAE AGER, 1965 Genus Cuneirhynchia BUCKMAN, 1918 Cuneirhynchia? retusifrons (OPPEL, 1861) (PL II, Fig. 3; Text-fig. 10) 1861 Rhynchonella retusifrons n.sp. - Oppel: p. 544, pi. 12, fig. 5. 187'4 Rhynchonella retusifrons OPPEL - Gemmellaro: p. 76, pi. 11, fig. 17. 71884 Rhynchonella cf. retusifrons OPPEL - Haas: p. 11, pi. 4, fig. 10. 1889 Rhynchonella retusifrons OPPEL - Geyer: p. 62, pi. 7, figs. 8-12. 71905 Rhynchonella cf. retusifrons OPPEL - Rau: p. 34, pi. 2, (22.), figs. 12-13. 1943 Rhynchonella cartieriformis n.sp. - Vígh: p. 47, pi. 3, figs. 6-7. Material: 2 complete specimens. Dimensions (mm): Specimen M.91.

10. (Text-fig. 10) length: 10.3, width: 12.4, thickness: 7.6. Description - External characters: Small shell, subpentagonal in outline. The sides of pentagon are slightly convex, except the one at the anterior margin, which is quite concave. The antero-lateral corners are slightly rounded. The angle between the lateral margins is about 110°. The width is greater than the length while the thickness is three-quarters of the length. Biconvex form, the brachial valve is more convex than the pedicle one. The maximum width and the maximum convexity are situated at half of the length. The beak is small and erect. There are two strong beak ridges running to half of the length on both valves. The lateral commissures are straight showing zig-zag deflections near the anterior margin. The anterior commissure is straight and also shows zig-zag deflections. The surface of valves is costate. The costae are stronger on the brachial valve than on the pedicle one. There are two costae more prominent than the others. These run from the umbo of brachial valve to the antero-lateral corners. The number of costae is 9 to 11, their cross-section is rounded triangular. The costae are absent or weakly developed at the umbo. There are some growth lines on the shell surface. Text-fig. 10 - Drawing of Cuneirhynchia ? retusifrons