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

at half of the length. The beak is small and suberect. There are two beak ridges on both valves, running to half of the length. The beak ridges are stronger on the pedicle valve than on the brachial one. The planareas are small and slightly concave. The lateral commissures run closer to the beak ridges of pedicle valve and divide the planareas in proportion of 1/4-3/4. The lateral commissures are straight at the planareas, than develop zig-zag deflections. The anterior commissure is strongly uniplicate and shows zig-zag deflections. The plica is trapezoidal. The width of plica is two-thirds of the total width while the height of plica is half of the total thickness. The shell surface is costate, on each valve 16 to 18 costae run straight to the anterior end without bifurcation. The costae are low and rounded triangular in cross-section. There is a weak capillation on the surface of planareas. The other form which occurs in the upper part of the section differs from the first one in the following features. This form is subtriangular in outline. The sides of triangle are slightly convex, the base is straight or slightly concave. The width is greater than the length while the thickness is significantly smaller than the other two values. Therefore this form is flatter than the other one. The maximum width is at the anterior margin. The beak is small and erect. The beak ridges of pedicle valve are stronger and the planareas are more concave than those of the other form. The beak ridges run to two-thirds of the length. The plica is wider but lower at the anterior margin than at the other form. Internal characters (Text-fig. 12): The dental plates are parallel. The delthyrial cavity is square in cross-section. The umbonal cavities are medium-sized and triangular in outline. No pedicle collar was observed. The hinge plates are slightly thick. The socket is wide, divided at an early growth stage but unified later. The teeth are slightly crenulated and there is a denticulum on their side. The teeth are aligned with the dental plates. The median septum is short, it is one-quarter of the total length. The crura are short, they are of radulifer type. Remarks: Oppel (1861) distinguished Rhynchonella cartieri from R. retusifrons in a footnote. In his opinion R. cartieri is narrower and thicker, the beak ridges of R. cartieri are sharper and the costae appear at the umbones. I agree with Geyer's (1889) statement that R. cartieri is synonymous with R. caroli described by Gemmellaro (1878). Vígh (1943) described a lineage in which R. cartieri is transitional between R. retusifrons and R. fraasi. In my opinion R. cartieriformis described by Vígh (1943) is synonymous with R. retusifrons. Geyer (1889) separated a new subspecies, R. rimata. Later Rossi Ronchetti and Brena (1953) separated another subspecies, R. depressa. The two forms in the section of Lókút Hill probably represent different ecotypes. The morphologically different specimens originating from two distinct plateaus (Dulai 1990) demonstrated that the two submarine plateaus differed in their physical parameters. The flatter specimens which occur in the upper part of the section are more similar to C. ? cartieri. Distribution: According to Aimeras (1964), C? cartieri is Hettangian to Early Sinemurian in age. The species was reported from Switzerland, the Eastern Alps (Hierlatz), the Southern Alps (Bergamo), the Northern Appennines (Monte Pisano), Sicily (Bellolampo), the Gerecse Mountains and the Bakony Mountains.