[Developmental cycle of the thorny-headed worm, Acanthocephalus lucii (Echinorhynchidae)].

The organogenesis of Acanthocephalus lucii was followed and its developmental periods established. In the organism of the intermediate host Asellus aquaticus the larva of A. lucii has three developmental stages: acantor, preacantella and acantella. At the average daily temperature of 25 degrees the developmental period from the egg to acantella completes within 19 days, at 22 degrees--in 32 days, at 19 degrees--in 51 days, at 18 degrees--in 60 days, at 15-16 degrees--in 72 days and at 15 degrees--in 89 days. In the intestine of fishes the worms become mature in three weeks after the infection. The excretion of eggs by females into the environment begins in 36-39 days after the worms have reached sexual maturity. The whole development of the worm in the definitive host lasts 57 to 60 days.