EN
The length of the uterus and the number of eggs stated in one ovulation do not evidence of the fertility of the helminth but of the development type of the eggs, rather. The fertility is defined by numbers of eggs secreted in a time unit. The structure and development state of the eggs is important. When eggs of complicated structure, in a state of almost full development (miracidium) leave the helminth, and their number is small, one can speak of low feritility (e. g. Schistosomatidae). When the uterus, however, contains more eggs with a thin pellicle, the eggs being in the initial phase of development - this is then an evidence of higher fertility (e. g. Plagiorchidae, Lecithodendriidae, partially Opistorchidae). Though the eggs through the uterus move raipidly they amass in great numbers.