Kirillov A. A. RussiaTogliattiInstitute of Ecology of the Volga River Basin, Russian Academy of Sciences, 10 Komzin Str., Togliatti 445003, Russiaparasitolog@yandex.ru Author's articles REPRODUCTIVE STRUCTURE OF A HEMIPOPULATION OF COSMOCERCA ORNATA (NEMATODA: COSMOCERCIDAE) IN MARSH FROGS PELOPHYLAX RIDIBUNDUS (PALLAS, 1771) (ANURA: RANIDAE) OF SEVERAL PHENOTYPES