| variability of hard parts of opisthaptor of two species of gyrodactylus nordmann, 1832 (monogenoidea) from phoxinus phoxinus (l.). | the morphological and metrical variability of hard parts of opisthaptor was studied in the representatives of local populations of gyrodactylus aphyae malmberg, 1957 and g. macronychus malmberg, 1957. the changes within the range of variability, which were observed during the year, correspond to regular and periodical changes in the environmental temperatures. the hard parts of opisthaptor were much smaller in specimens occurring during warm seasons than in specimens occurring during cold season ... | 1976 | 1278817 |