CESTOIDEA. 



383 



The mature Tape-worm consists of 

 head, neck, and joints. The young 

 tape-worm or Hydatid or Scolex or 

 Cysticercus (from the Gr. kustis, a 

 bladder, and kerkos, a tail) or u blad- 



Fio. 518. 



A Larval Tape-worm or Hyda- 

 tid (Cysticercus) five times 

 the natural size. 



a, circle of booklets; b, suck- 

 ing disks; c, neck; d, water- 

 bladder. (From Weinlaud's 

 " Human Ceatoides.") 



der-tail," has only a 

 head, a neck, and 

 a " water-bladder." 

 The neck is constant- 

 ly growing from the 

 head, and the trans- 

 verse wrinkles of 

 the neck become the 

 joints or " proglot- 

 tides" of the body. 



1. Human Tape-worm, Tcenia solium, Linneeus natural size. Only characteristic 



parts represented. 



H. head; a, 309th joint; 6, 448th joint; c, 569th joint; d, 680th joint; e, 768th joint; 

 /, 849th joint; g, 855th joint. 



2. Mature joint of the same, showing the ovary, and ovarian opening (o). 

 This worm measured 103-4 feet. (From Weiuland's " Human Cestoidea.") 



