152 WORMS. 



DIAGRAM VII. 



Fluke and Tapeworm. 



The lower half of the diagram shows the life-history of Distomum. 



a, is the embryo still within its egg-shell. 



b, is the free-swimming ciliated larva with eye-spots. 



c, is the sporocyst with rediee formed within it. 



d, is a single redia with reproductive cells. 



e, is another redia with more redi« within it. 

 7^ is a redia with cercarise formed within it. 



g, is a cercaria, with tail, forked gut, and two suckers. 

 h, is a young fluke, without tail, with branched gut. 



The upper half of the diagram shows the life-history of Taenia. 



Begin with the six-hooked embryo within its egg-shell. It becomes 

 a bladder- worm or proscolex, first (A) with inverted, and then (B) with 

 everted "head" or scolex. 



The " head " is shown enlarged ; the suckers and hooks and the. first 

 joints are obvious. 



Fragments of a complete tapeworm are also depicted, shovring the 

 minute head, and the increasing size of the joints or proglottides. 



