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

Internal characters (Text-fig. 34): The dental plates are divergent. The delthyrial cavity is trapezoidal in cross-section. The umbonal cavities are large and rounded in cross-section. No pedicle collar has been observed. The hinge plates are short and narrow. There is a shallow septalium. The socket is not too large. The teeth are aligned with the dental plates and slightly crenulated. No denticulum has been observed. The median septum is short comprising one-quarter of the length. Most of the loop is missing. Remarks: The "box-like" appearance and the outstanding commissures suggest close relationship to Zeilleria venusta. However, the circular outline differs from Z. venusta. For more precise determination and description, more and better preserved specimens would be needed. Zeilleria cf. livingstonei GEMMELLARO, 1878 (Pl. V, Fig. 5; Text-figs. 35-36) 1878 Zeilleria livingstonei n.sp. - Gemmellaro: p. 418, pi. 29, figs. 28-33. 1895 Waldheimia livingstonei GEMMELLARO - Fucini: p. 209, pi. 7, fig. 32. Material: 2 complete specimens. Dimensions (mm): Specimen M.91.31. (Text-fig. 35) length: 17.2, width: 14.9, thickness: 9.4. Description - External characters: Medium-sized shell, subtriangular in outline. The antero-lateral corners are quite rounded. The sides of triangle are slightly convex, the base is quite convex. The angle between the Text-fig. 35 - Drawing of lateral margins is about 55°. The length is Zeüleria cf. livingstonei greater than the width while the thickness is about half of the length. Biconvex form, both valves are equally convex. The maximum width is situated at the anterior margin while the maximum convexity is at the posterior third. The beak is medium-sized and erect. There are two weak beak ridges on the pedicle valve, running to half of the length. The commissures are straight. There is a weak capillation on the shell surface. Internal characters (Text-fig. 36): At early growth stages the dental plates are divergent and the delthyrial cavity is trapezoidal in cross-section. Later the dental plates become parallel and the delthyrial cavity is rectangular in outline. The umbonal cavities are large and rounded in cross-section. No pedicle collar has been observed. The hinge plates are short. There is a deep and wide septalium. The socket is shallow but relatively wide. The teeth diverge from the dental plates. The teeth are slightly crenulated and wide in the socket. The median septum is short, it is about one-quarter of the length. Most of the loop is missing. Remarks: In the original description Gemmellaro (1878) represented two forms: a pentagonal and a triangular one. The triangular form is long, its beak is wide and hood-like. It shows resemblance to the material of Lókút Hill. The beak are absent from all our specimens but the hood-like broadening is clearly visible.