1 66 



UNSEGMENTED "WORMS." 



this remains quiescent, and without power of further develop- 

 ment, unless the pig be eaten by some other Vertebrate. 



When man unwittingly eats " measly " pork, that is pork 

 infested with bladder-worms, an opportunity for further 



v.d 



t.e. 



Fig. 73. — Diagram of reproductive organs in Cestode joint. 

 — Constructed from Leuckart. 



ov., Ovary, with short oviduct; «/., "uterus;" t., diffuse testes ; 

 sk.g., shell gland; y.g., yolk gland ; v.d., vas deferens ; v., vagina; 

 r.s., receptaculum seminis ; i.e., longitudinal excretory ducts ; 

 t.e., transverse bridges connecting these. 



The dotted lines above and below represent the anterior and 

 posterior borders of the proglottis. Note that the so-called uterus 

 is blind; it opens to the exterior in a few tape-worms, and is 

 perhaps the homologue of the Laurer-Stieda canal of Trematodes. 



development is afforded. The bladder is lost, and is of no 

 importance, but the "head " or scolex fixes itself to the wall 

 of the intestine. There it is copiously and richly nourished, 

 and buds off asexually a chain of joints. 



