The liver-fluke (Distomum hepaticum) unlike most Trematodes flourishes in a wide range of hosts and infects man, horse, deer, oxen, sheep, pig, rabbit and kangaroo.
Occasionally the fluke migrates into the blood vessels and may reach the lungs, kidneys, urethra and bladder.
The body contains in miniature all the organs of the adult fluke, including the gonads and in addition "eye-spots," a stylet, rod-cells and cystogenous cells.
Whether this view is soundly based is discussed below; the fact remains, however, that a tapeworm is, with few and rare exceptions, not directly comparable at all points with a liver-fluke or indeed with any other organism.
The former fluke is found in Europe, North Africa, Abyssinia, North Asia, South America, Australia and the Hawaiian Islands; the latter in the United States.
When that occurs, the cyst is dissolved and the minute fluke works its way down the alimentary canal into some part of which it inserts its suckers and commences to feed on the blood of its host.
The liver-fluke (Distomum hepaticum) passes through its larval stages in the water snail Limnaea truncatula in Europe; in L.
Sommer, "Anatomy of Liver-fluke," Zeit.
Truncatulus harbours the Cercaria of Fasciola hepatica, the liver-fluke, which causes rot in sheep. Ancylus, which occurs in rivers, has a minute limpet-like shell.
Much of the grain was never harvested, whilst owing mainly to the excessive floods there commenced an outbreak of liver-rot in sheep, due to the ravages of the fluke parasite.