116 



ZOOLOGY. 



sufficient to kill the Cysticerci. Butchers especially suffer 

 from tape-worms, from their habit of eating bits of raw 

 meat, beef and veal harboring Cysticerci, which transform 

 into species of Tcenia nearly as injurious as Tcenia solium. 

 As a matter of course, in the use of drugs to expel a tape- 

 worm, they should be pushed so as to carry off the entire 

 animal, as new segments grow out from near the head as 

 rapidly as the proglottides are detached. 



The Cysticercus of another injurious tape-*vorm lives in 

 the muscles and internal organs of cattle. This is the Tcenia 



mediocanellata of Kuchen- 

 meister, which is larger,, 

 with a larger darker head, 

 larger suckers, and with- 

 out a rostrellum or hooks. 

 By far the most injurious 

 species is Tcenia echinococ- 

 cus Siebold (Fig. 78), 

 more frequently causing 

 death than any other en- 

 tozoon. In its adult or 

 strobila state this worm 

 only infesbs the dog and 

 wolf, but its larva, the 

 hydatid of physicians, fre- 

 quently occurs in the hu- 

 man body. It is very 

 small, seldom exceeding; 

 six millimetres in length, 

 there being but four 

 segments, including the 

 head, which has a pointed 

 *lf rostellum, with a double 

 crown of large-rooted 

 hooks ; there are four suckers present, and the last segment, 

 when sexually mature, is as long as the anterior ones taken 

 together. The hydatid (proscolex) forms large proliferous 

 vesicles, in which the scolices (Echinococcus heads) are de- 

 veloped by budding internally. About five thousand egg? 



rig. 77. -FrogiottiB of T. sdium, a, testis 





