PLATYHELMINTHES 



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Fig. 32. Life-history of Fasciola hepatica. A, "egg"; B, miracidium; C, sporo- 

 cyst; D, E, rediae; F, cercaria; G, tail-less encysted stage; E, adult (neither reproduc- 

 tive organs nor nervous system is shown), b.o. Reproductive opening of redia; c, 

 cercaria; E, egg; ent, intestine; g, nerve-ganglion; g.c, germ-cells; g.l, cyst-producing 

 gland-cells; n, nephridium (only a few of the main branches of the excretory network 

 are shown); n.o, nephridial opening; o.s, oral sucker; p, proboscis (extruded); v.s, 

 ventral sucker; y, yolk-cells. (After Kerr. Courtesy of Macmillan and Co., Ltd.) 



