EN
A change in the kind of food being introduced on one of the breeding farms investigated previously (Malczewski, 1962) additional examinations were undertaken in Alopex lagopus L., deriving from this farm and fed now with sea-fish fall-offs. The helminthofauna of the animals has undergone important changes (Table). All animals under examination showed a massive Cryptocotyle concavum (Creplin, 1825) invasion, whereas in the previous studies the parasite was found in only one animal; its massive incidence was also encountered in other farms. C. concavum is a species typical of birds, being met only sporadically in mammals.