182 



EMBRYOLOGY 



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Fig. 8fl. — A to G, course of development of Vistomum hepaticvm (after Leuckart) : 

 A, larva with eye-spot {A), with ganglion lying under it and germ cells (Kz) ; B, 

 young sporocypt, with masses of germ cells inside of it, from the respiratoiy cavity 

 of the snail ; C, older eporocyst, with young Redia? ; D, Redia, with Redi^ and 

 germ halls inside of it, from the liver of the snail ; E, Redia, with Cercari» 

 and germ balls, from the liver of the snail; F, free-swimming Cercaria; O, 

 young liver-fluke from the bile-duct of the sheep, with branching of the in- 

 testine already begun. ^, eye-spot : 7), intestine; Vr, glandular mass on either 

 side of the body of the Cercaria; Ea-, excretory system; G, birth aperture of 

 the Redia; Kz, germ cells; N, nervous system. 



