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TEXTBOOK OF ZOOLOGY 



Other important flukes are the human intestinal fluke, Fasciolopsis 

 huskii, which is common among the Chinese, who become infected by 

 eating the cysts on various aquatic food plants; the human lung 

 fluke, Paragonimus westermanii of eastern Asia, where the natives 

 become infected by eating the encysted larvae in fresh-water crabs 



Fig. 399. — Life history of the liver fluke. Fasciola hepatica. A. adult in liver of 

 sheep ; B, freshly passed egg as it leaves the body of the host ; C, developing em- 

 bryo, ready to hatch in the water ; D^ ciliated miracidium embryo in the water and 

 about to enter the pulmonary chamber of snail ; E, F, sporocyst containing rediae ; 

 G, redia containing daughter rediae ; H, redia of the second generation containing 

 cercaria ; J, same having emerged from snail into water ; K, cercaria encysted on 

 blade of grass ; L, cercaria liberated from cyst after ingestion by sheep ; M, young 

 fluke developing in liver of sheep. (Reprinted by permission from Chandler, 

 Introduction to Human Parasitology, published by John Wiley & Sons Inc.) 



