CESTODA OR TAPEWORMS. 47 



Billiai-zia TiwmahMa. — This trematode lives in the veins of 

 the bladder in man, especially in abundance on the east coast 

 and inland parts of Africa from Egypt to the Cape and around 

 Lake Nyassa and the Zambesi river, Gold Coast, Mecca, &c. 

 In Egypt, 30 per cent of the population suffer from Haematuria, 

 the disease caused by this worm. It is found in couples, chiefly 

 in the veins of the bladder, pelvic region, and large intestine. 

 The expelled urine is mixed with blood and eggs of the worm. 

 The female is filiform, about 20 mm. long, and is found in a 

 canal along the male, which is white, and from 12-14 mm. 

 long. 



Another species, B. crassa, infests cattle in Egypt, Sicily, 

 and India, but does not produce hasmaturia. 



The Polystomata are external parasites, and develop without 

 any alternation of generations such as we have just seen in the 

 liver-fluke of the sheep. Some species live in the bladder of 

 frogs {Polystomwn interrimum), others live on the gills of fish 

 (P. lanceolatum). 



Cestoda or Tapeworms. 



The Tapeworms are a group of flat-worms which are entirely 

 parasitic in habits. They are segmented, but not in the same 

 sense as we understand the segmentation of the true Oligochaeta. 

 There is neither a mouth nor an alimentary canal, as the nutri- 

 ment is taken in by the process of endosmods, absorption being 

 effected through the skin of the whole body-surface. These 

 cestode worms undergo a curious alternation of generations. 

 The two stages in the cestode life - cycle have often been 

 described under two different names. The two stages are — 



(1) the adult worm, which is always found living in the 

 intestines of man and various animals and birds, &c. ; and 



(2) the " cystic stage," which is usually found in a totally 

 different host, and in some of the organs or connective tissues 

 of the body, not in the intestines. The diseases produced by 



