[Arthropods found on European beaver (Castor fiber L.) in Poland]

In July 1988, arthropods from 6 Castor fiber were collected at Popielno near Ruciane. Schizocarpus numerosus Dub., S. fedjushini Dub., S. brachyurus Dub. are new to the fauna of Poland. Ixodes hexagonus Leach (larvae, nymphs, females) is especially numerous. Under-development of the coxa and trochanter of the third left leg was noted in one female. Moreover, Acarus farris (Oud.), Cunaxoides kielczewskii Mich. and unidentified female of the Phytoseiidae were obtained. Cunaxid mites have not been collected hitherto from mammals. At the present time in Poland, 8 species (including Platypsyllus castoris Rit.) of arthropods are found on C. fiber.