1 62 



UNSEGMENTED "WORMS." 

 2 3 



Fig. 72. — Life history of liver fluke. — After Thomas. 



1. Developing embryo in egg -case; 2. free -swimming ciliated embryo; 

 3. sporocyst; 3a. Shell of Limneeus^ truncatulus ; 4. division of sporo- 

 cyst ; 5. sporocyst with redise forming within it ; 6. redia with more 

 rediie forming within it ; 7. tailed cercaria ; S. young fluke. 



