Dr. Murai Éva szerk.: Parasitologia Hungarica 18. (Budapest, 1985)

The size of F. buski shows remarkable variability even in the same host specimen. They reach maturity in fifty days post infection and their measurements at this age are about 10.0 by 3.9 mm. The dimensions of the internal organs are positively correlated with their body size (Table 2; data of this table contains the average number of five measured specimens). The genital organs of 10-days old specimens are not yet observable In 20-day-old worms, the genital organs appeared in a knot form: the ootype is only a small point, ovary is a small hook, in the ootype the uterus and vitelline ducts are two small tubes running parallel. At 25 days, the genital organs have already developed, however, their structure is still simple, the first convolutions of the uterus appear, the ovary and the testes are still small. Infectivity of metacercariae and number of recovered flukes 1 Age of metacercariae (days) Number of metacercariae Number of recovered flukes Percentage take 1 1 206 84 40.8 2 5 166 75 45. 1 3 10 67 18 26. 8 4 15 168 33 19. 6 5 20 191 23 26. 8 6 25 160 43 12.0 7 30 195 57 29. 2 8 30 178 7 3.9 9 35 208 11 5. 2 10 35 33 5 15. 1 11 40 180 2 5 13. 8 12 40 188 5 2. 6 13 45 243 56 8.2 14 45 48 1 23.0 15 50 111 12 10. 8 16 50 50 4 8.0 17 55 243 18 7. 4 18 55 205 5 2. 4 19 60 110 8 7. 2 20 60 143 6 4. 1 The growth of 30-40 days old F

. bu ski is very fast not only in body size but also in dimensions of the genital organs. The ovary and testes grow rapidly, the secondary branches of the latter organs are observable. The developing uterus forms a lot of convolutions. The vas deferens becomes strong and goes down, the Mehlis glands are thick (Fig. 1). The genital organs mature at an age of 50 days. The large uterus has a great number of uterine convolutions situated between the ventral sucker and the ootype; some of the flukes have already matured eggs in the uterus. This suggests that F. buski discharges eggs in 50-65 days after infection (Fig. 2).