288 



PL A THELMINTHES. 



Many other Tcenice, which are common to other mammals, occur occa- 

 sionally in the human intestine. In mice and rats occur T. (Hymenolepis} 

 murina and T. diminuta (= leptocephala). The first (identical with T. 

 nana) has recently been very abundant in human intestines in Italy. The 

 worm, an inch or two long, may occur in thousands and cause severe in- 

 jury. This species may develop without an intermediate host ; the eggs 

 taken into the stomach pass the cysticercoid stage in its walls and thence 

 to the intestine to become adult. T. diminuta (=flavopunctata), which 

 has insects for its intermediate host, has been described from man. Other 

 species occur in the tropics. 



B. Forms passing the Cysticercus stage in man. Besides the Cysticercus 

 cellulosae of T. soliitm that of T. acanthotrias 

 (possibly identical with T. solium) has been 

 found in man. More frequent and of more im- 

 portance to the physician is the Cysticercus of 

 Tcenia echinococcus (fig. 253), which lives as an 

 adult in the dog, and is easily overlooked on ac- 

 count of its size. It is at most 5 mm. ( inch) long 

 and consists of a scolex and three or four pro- 

 glottids. The scolex bears four suckers and hooks 

 on the rostellura. When the eggs are taken into 

 the human stomach, as may easily happen by 

 stroking and kissing infected dogs, the embryos 

 are set free and wander into liver, lungs, brain, 

 or other organs and produce here tumors which, 

 * n tne case ^ * ne ^ ver ' ma y weigh ten or even 

 Right sexually mature; thirty pounds. This extraordinary size is ex- 

 left a part of an echmo- i_ . . j.- c j 

 coccus with two brood plained by the formation of daughter bladders 



lices UleS and their 8C " (echinococcus) described above. Echinococci are 

 more common in cattle, sheep, and swine than in man. 



Common Tcenice of domestic animals are in the horse Anoplocephala 

 plicata (4 to 30 inches), A. perfoliata ( to 3 inches), A. mamillana (i to 



