566 TiENIA MAEGINATA AND CYSTICERCUS TENUICOLLIS. 



a good illustration of what we have already said in connection with Cyst. 

 ceUulosce, and shall again have to notice regarding the Echinococciis. 



Further Details regarding the Adult Tape- Worm. 



Leuokart, " Blasenbandwurmer," p. 59. 



Baillet, "Exp&ience sur le Cysticercus tenuicoUis," &c., Ann. sci. nat. (Zool.), sfer. 4, 

 t. xvi., p. 99, 1861. 



Krabbe, " Eecherches helminthologiques," p. 3: Copenhagen, 1866. 



■ In the alimentary canal of the dog there live, besides the above 

 described Tcenia marginata,^ two other large-jointed, large-hooked 

 tape-worms, viz., T. serrata (e Cysticerco pisiformi) and T. ccenums (e 

 Gcenuro cerebrali). These do not pass into man,^ but are, neverthe- 

 less, worthy of mention if only because they have so often been 

 confused with one another, and with T. solium. The T. ccenurus, 

 besides, is among the most dangerous of all Helminths, because its 

 young brood causes the " staggers " of lambs, and thus inflicts great 

 loss upon the farmers. Formerly it was still more common, for we 

 now strive to protect our flocks from being infected by the dogs asso- 

 ciated with them. 3 



As to the resemblance which T. marginata has both to T. serrata 

 and to T. ccenurus, this is most marked in the former instance ; for T. 

 serrata has almost the same external appearance and approximately 

 the same size (it is sometimes over a metre in length). T. canurus, 

 on the other hand, is full grown at a length of 30 to 40 em., and, 

 besides this, remains much more slender than either of the others. 

 The chief differences, however, are seen in the structure of the head 

 (i.e., of the hook- apparatus) and of the uterus. 



Fig. 306. — Larger and smaller hooks of Tcenia serrata. ( x 280.) 



Tcenia serrata has by far the largest head (1'3 mm.), the most 

 conspicuous suckers (0-4 mm.), and the strongest armature. The 



' In the countries where the reindeer abounds T. Krabbei is also found (p. 405, note). 



^ The assertion that the Ocenurus also occurs in man is based on a misconception, 

 which arose from the unfortunate use which Zeder made of the same generic name (Poly- 

 cephalus) in reference both to Echinococcus and Ccenurus. 



° Through the kindness of the well-kno^vn breeder v. Nathusius-Hundisburg I am able 

 to state that he has thus re^'M(^;^g)^|^^H^^[^©gg)g(®cent. to from 1 to 2 per cent. 



