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

belong new bryozoan taxa as well as new ichnotaxa. The determination of the correct systematic place needs further studies. The coexistence with Proconulus baldensis and the characters of the excavation system indicate a parasitic mode of life. The bryozoan larva could have recognized the suitable host by chemoreception and settled at the parietal lip, certainly after passing through the mantle cavity by the respiratory current. From the ancestrula, the earliest (or an early) stolon (i.e. primary stolon, Pl. Ill, fig. 1; Text-fig. 1) grew to the periphery and further to the suture. The bryozoan used the shell structure of gastropod to maintain the orientation of the stolons with nearly constant angle to growth lines. The frontal kenozoecia must have been able to recognize the other parts of the colony before reaching them. This is why the stolons (their excavations) have never crossed each other. As a consequence, the majority of the younger branches were directed toward the peristome. Beside this constructional force, the stolons, terminating at the peristome may have also had a role in orienting the new branches to follow the source of food. ACKNOWLEDGEMENT The author is indebted to Dr. L. Kordos (Hungarian Geological Survey) for his help in taking SEM photos. REFERENCES BASSLER, R. S. (1953): Bryozoa. In: MOORE, C. M. (Ed.): Treatise on Invertebrate Paleontology. Part G - Lawrence, 253 pp. BROMLEY, R. G. (1970): Borings as trace fossils and Entobia cretacea Portlock, as an example. In: CRIMES, T. P. and HARPER, J. C. (Eds.): Trace Fossils. - Liverpool, p. 49-90. CONTI, M. A. and SZABÓ J. (1987): Comparison of Bajocian gastropod faunas from the Bakony Mts. (Hungary) and Umbria (Italy). - Annls. hist.-nat. Mus. natn. hung, 79:43-59. GLAUB, I. (1988): Mikrobohrspuren in verschiedenen Faziesbereichen des Oberjura Westeuropas (vorläufige Mitteilungen). - N. Jb. Geol. Paläont, Abh, 177:135-164. HARY, A. (1987): Epifaune et endofaune de Liogryphaea arcuata (Lamarck). Trav. Scient. Mus. Hist. Natur. Luxembourg, 10:1-79. SEULE, J. D. and SEULE, D. F. (1969): Systematics and biogeography of burrowing bryozoans. - American Zoologist, 9: 791-802. SZABÓ, J. (1979): Lower and Middle Jurassic Gastropods from the Bakony Mts. (Hungary). Part I: Euomphalidae (Archaeogastropoda). - Annls. hist.-nat. Mus. natn. hung, 71:15-31. SZABÓ, J. (1980): Lower and Middle Jurassic gastropods from the Bakony Mts. (Hungary). Part II: Pleurotomariacea and Fissurellacea (Archaeogastropoda). - Annls. hist.-nat. Mus. natn. hung, 72:49-71. SZABÓ, J. (1981): Lower and Middle Jurassic gastropods from the Bakony Mts. (Hungary). Part III: Patellacea and Trochacea (Archaeogastropoda). - Annls. hist.-nat. Mus. natn. hung, 73: 55-67.