ANIMAL PARASITISM 



453 



also differ from trematodes by having the body divided into a series 

 of segments, one behind the other, each segment having a complete 

 set of reproductive organs. This structure characteristic of tape- 

 worms is usually referred to as segmentation of the body, but it is 



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Fig. 193. — Structure of tapeworm to show different stages of maturity. At 

 lower left, Taenia pisiformis scolex with hooks and sucker discs. At lower right, 

 mature proglottids. Above, scolex and proglottids of three ages. The reproductive 

 organs and pore are shown in most proglottids. (Courtesy of Ward's National 

 Science Establishment, Inc.) 



