Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 18. 1996. (Budapest, 1996)

The rarity of benthic macro-invertebrates in basinal areas as compared to their relative frequency on submarine highs can clearly be explained by the reduction of the amount of available food, i. e. the suspended organic material, with the increasing depth (VÖRÖS 1973). ACKNOWLEDGEMENTS Prof. B. GÉCZY made the Pliensbachian bivalves of the Bakony Mts. available for study. Several specimens were kindly donated by Dr. A. VÖRÖS and Dr. A. GALÁCZ. Dr. J. SZABÓ encouraged the author to study the fauna. Their help and kindness is gratefully acknowledged herein. The work was supported by the OTKA (Hungarian National Research Fund, Grants No. T. 4431 and F 7329). APPENDIX Remarks on Praechlamys rollet (Stoliczka, 1861) and description of Eopecten johnsoni sp. n. One specimen of P. rollei from the former manganese-ore mine at Eplény (Pl. I: 6) has been preserved with traces of the outermost shell layer, which shows very fine antimarginal striation (Pl. 1: 7), an unusual feature in Praechlamys (WALLER & MARINCOVICH 1991). The fine "radial" striae observed by CONTI & MONARI (1991) on valves of P. rollei from the Lower Jurassic of Turkey are most probably also antimarginal ones. During examination of the Pliensbachian bivalves, 13 valves of Eopecten were found, which could not be assigned to any species previously described in the literature. They were referred to as Eopecten sp. by SZENTE (in press) and now are described as Eopecten johnsoni sp. n. Eopecten johnsoni sp. n. (Pl. I: 9-10) Holotype: a left valve housed in the Department of Palaeontology, Loránd Eötvös University, Budapest (EUŐT 96/1). Name: After Andrew L. A. JOHNSON, researcher of Mesozoic scallops. Type strata: Red fissure-filling limestone of the Margaritatus Zone (Upper Pliensbachian). Type locality: Eplény, former manganese-ore mine. Material: Five left valves from the Hierlatz limestone of the Kericser Hill, seven left valves and a right one from the former manganese-ore mine at Eplény. Diagnosis: Medium-sized Eopecten with very numerous fine, radial costae. Measurements (mm): Height 19.2 37.6 (holotype) 36.3 Length: 18.0 — 34.1 Length of left anterior auricle: 6.3 12.2 11.2