254 



TLATIIELMINTIIES 



(fig. 225). Immature and mature stages in lishcs. Tclrarhyiichus,^ Ryncho- 

 bolh rill })!.''' Family 4. TETR.\riiYLLiD.E. Head with four vcr)- mobile suckers, 

 often armed wilh I'looks. Echinobolhriuni:' Aiaii/hoho/liriiiiii/' 



Family 5 Botheiocephalid.k. Scolex anil progloltids present; liead 

 spalulale, with two sucking groo\es on the 

 narrower sides. Bo/hrioicplia/iis la/US'^ (fig. 

 234), the largest tapeN\orm in the human intes- 

 tine (,also dogs and cats), mav reach a length 

 of forty feet anil consist of oxer iouv thousand 

 progloltids. As said al)o\-e, the pleurocercoid 

 occurs in hshes, and man acipiires the parasite 

 by eating uncooked I'lsli. It is abundant in 

 Russia, I'russia, ancl Switzerland; rare in 

 America. 



l'"aniily 6. T.kxl\d.e. A\'ilh scolex and 

 separable progloltiiis; the scolex always bears 

 four suckers and in many a roslelluni \yilh a 

 circle of hooks (fig. 234). In the progloltids 

 the genital )iore occurs usually laterally in the 

 proglotlids, alternating right and left, rarely 

 onl\- on one side. It is rarely doubled in a 

 proglottid. Intermediate stage a cyslicercus or 

 cyslicercoid. The human tapeworms are here 

 subdiyided accordingly as the sexual animal or 

 the C)'sticercus has been found in man. 



.1. TiCiiicc sexually mature in the human 

 inleslinc. Most noticeable are Tuiiia soliiiiii'^ 

 and T. .s'ij^'/h(1/i7,* the differences between which 

 are shown in fig. 234. In spite of the lack of 

 h.ioks, the stronger suckers render 7". soi^iiuita 

 more difficult to expel. Tuiiia solium is not 

 rare in the cysticercus stage in man and occurs 

 sometimes in places, like the brain and eyes, 

 where it causes seyere injury. These cases are 

 in part explained by lack of cleanliness in the 

 food, which may contain eggs, but possibly 

 occur through internal infection; pieces of the 

 ^vorm passing the pylorus and entering the 

 stomach, where they are digested, setting the 

 embryos free. 



Many oilier Ti(-}ii<r, which are common to 

 other mammals, occur occasionally in the 

 human intestine. In mice and rals occur T. 



Fio. j;,:;, — CarynpIiyU^nis 

 nuifahiUs (after !\I. .'-^chullzcl. 

 df, yas deferens; (/;■, \ilelline 

 duel: /,'. scole\"; ov, oyaries; f's. 



penis; f,r, x-.igina with reeepta- (H yiiirnolrf'is) ii,Jna-= and T. diniiiiida. The 



first has recently been \erv abundant in human 

 intestines in Italy and is probably common with 

 us (fig IT2~). The worm, an inch or two long, 

 may occur in thousands and cause seyere injury. 

 This species may deyelop without an interme- 

 diate liost; the eggs taken into the stomach pass 



the cyslicercoid stage in its walls and then pass to the intestine to become 



adull. T ilimiinila.''' which has insects for its intermediate host, has been 



described from man. 



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



culum seminis; /, teste:?; ill 

 uterii.s; -ri, Wtelkirium; vs. ycsi- 

 cula seminalis. The conncclion 

 of yagina with the crossing point 

 of rrenital duct, yilelline duet, 

 and uterus is lacking; in the figure. 



