Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 14. (Eger, 1995.)

DÁVID, Á.: Naticid prédation on Late-Oligocene (Egerian) corbulid bivalves collected from three localities of NE - Hungary

be observed on a right valve of a specimen. There are four borings on it. One of them is complete, one is unfinished and two are nonfunkctional. The latters are situated on the edge of the valve (Ansell, A.D. - Morton, B. 1983). Number of borings on the right and left valves is similar in the case of the x - layer. The same conclusion can be drawn with the examination of the boreholes found on Corbulas of the k - layer. Borings on the right valves are more frequent (Fig. 2). Table 1. Distribution of naticid predatory boreholes on the valves of Corbula basteroti Homes collected from different layers of Wind Brickyard according to boring types A: complete boring, B: nonfunctional boring, C: unfinished boring Corbula basteroti Homes Locality Numbers of individuals Valve bored Left valve Right valve Locality Numbers of individuals Valve bored A B C A B C Wind Brickyard Molluscan Clay 2 1 1 2 1 Wind Brickyard x-layer 50 7 1 2 1 1 1 1 Wind Brickyard k-layer 44 6 1 2 1 2 Naticid predatory boreholes on the valves of Corbula gibba Olivi Specimen were collected from three localities (Table 2). 28,1 percent of the valves was bored. Multiplied borings can be observed in two cases. There are two borings on a left valve collected from the molluscan clay of Wind Brickyard. These are complete and nonfunctional borings. While in the case of a right valve collected from the molluscan clay of Nyárjas Hill two unfinished borings can be studied. The majority of the boreholes can be found on the right valves (Fig. 3). Table 2. Distribution of naticid predatory boreholes on the valves of Corbula gibba Olivi collected from different layers of three localities according to boring types A: complete boring, B: nonfunctional boring, C: unfnished boring Corbula gibba Olivi Locality Numbers of individuals Valve bored Left valve Right valve Locality Numbers of individuals Valve bored A B C A B C Wind Brickyard Molluscan Clay 23 3 1 1 2 Wind Brickyard x-layer 28 9 3 1 5 Rozália cemetery Molluscan Clay 11 4 1 1 2 Nyárjas Hill Molluscan Clay 2 2 3