Studies of the Helminth Fauna of Norway XXXIV: The morphological stability of Diphyllobothrium Cobbold. A comparison of adult D. dendriticum (Nitzsch), D. latum (L.) and D. ditremum (Creplin) developed in different hosts

Abstract

Adult D. dendriticum from common gull {Larus canus), herring gull (Larus argentatus) and arctic fox (Alopex lagopus), D. latum from arctic fox, and D. ditremum from merganser (Mergus merganser) were studied. A comparison with worms reared in golden hamster (Mesocrisetus auratus) was conducted. Morphological characters of reliable diagnostic value (characters independent of host and worm population size) are: neck length, type of boundary between neighbouring segments, position of the cirrus-sac in sagittal sections, position of seminal vesicle in relation to the cirrus-sac, and shape of ovary (ovary with or without anterior horns)