260 



PLATYHELMINTHES. 



hooks. Development by means of Cysticerci (bladder- worms). Both 

 bladder-worm and tape-worm stage in mammals. Tacnia L. (Cystolaenia 

 R. Lkt). The vesicles of the Cysticerci are large. The heads arise from 

 the bladder of the Cysticercus. 



T. soli urn. L. 2-3 metres long. A double circle of 26 hooks. The ripe 

 proglottides are 8-10 mm. long and 6-7 mm. broad ; the uterus has 7-10 

 dendritic branches (Fig. 202). It lives in the human intestine. The 

 bladder-worms belonging to it (Cysticercus cellulosae] live principally in 



the dermal cellular tissue and in the muscles 

 of pigs, but also in the human body (muscles, 

 eyes, brain), in which self-infection with them 

 is possible if a Tacnia is present in the digestive 

 canal ; more rarely in the muscles of the roe- 

 deer, the dog, and the cat. In the human brain 

 the Cysticercus acquires an elongated form, and 

 sometimes does not produce a head. 



T. saginata Goeze = mcdiocanellata Kiichenm., 

 in the intestine of man, distinguished by the 

 older helminthologists as a variety of T. sofin.m. 

 Head without circle of 

 hooks or rostellum, but 

 with four more power- 

 ful suckers. The tape- 

 worm reaches a length 

 of four metres, and 

 becomes much stronger 

 and thicker. The ma- 

 ture proglottides are 

 about 18 mm. long 

 and 7-9 mm. broad. 

 The uterus forms 20-3? 

 dichotomous side 

 branches (Fig. 202). 

 The Cysticercus lives 

 in the muscles of the 

 ox (Fig. 218). It ap- 

 pears to be principally 

 distributed in the 

 wanner parts of the 

 Old World, but is 

 often found in great numbers in many places in the north. It is the 

 common tape-worm of the Abyssinians. 



T. scrrata Goeze, in the intestinal canal of the dog. The Cysticercus 

 is known as Cysticercus pisiformis in the liver of the hare and rabbit. 

 T. crassicollis Rud. in the cat, with Cysticercus fasciolaris of the common 

 mouse. T. marginata Batsch. of the dog (butcher's dog) and wolf with 

 Cysticercus tenuicollis from ruminants and pigs, and occasionally in man 

 (Cyst, visceralis}. T. cmssiceps Rud. in the fox with Cysticercus longicollis 

 from the thoracic cavity of the field-mouse. T. cocnurus v. Sieb. in the 

 intestine of the sheep-dog with Coenurus cercbralis in the brain of one-year- 

 old sheep causing staggers. The presence of Coenurus in other places has 



FIG. 217. Scolex of Ti' 

 Ghusruficollis, showing the four 

 hooked proboscises protruded 

 and two of the suckers (after 

 van Beneden). 



FlO. 218. dinticercus of 

 Taenia sitgi nata (mediia-n- 

 ncllata), magnified about 

 eight times. The head is 

 protruded (from Clans). 



