//. TREMATODA : DISTOME^^. 



277 



kin-seed. It lives in the bile-ducts of sheep, cows, pigs, etc., and rarely 

 (twenty known cases) of man. It stops up the ducts and causes a disease 



DEVELOPMENT OF DISTOME^. 

 (a) Simple ih) Ordinary (fl Complicated 



known as 'liver rot,' generally resulting 

 described above shows why sheep pastured in 

 the disease, and why wet seasons are times 

 rainy year of 1830 about one and a half mil- 

 lions of sheep were killed in England ; in 

 1,S12, 300,000 in the neighborhood of Aries, 

 France. This species is frequently accom- 

 panied by D. lanceolatum, less than half an 

 inch in lengtli (fig. 233). 



Bilharnaluvmatohia is a human parasite, 

 most enmmon in hot climates, and especially 

 so among the Fellahin of Egypt. The sexes 

 are separate. The male, half an inch long, by 

 inrolling of the ventral side (fig. 237) forms 

 an incomplete canal (canalis gyniecophorus) 

 in which the more slender female usually lies. 

 Tliese united worms occur in the portal vein 

 and CDunected vessels. They follow these 

 vessels in eitlier direction and lay their eggs 

 in tlic mucous membrane of the ureters and 

 urinary bhidder, as well as in liver and intes- 

 tine. The suppurative sores of the urinary 

 tract cause albuminuria or, by hemor- 

 h;ige, hreniaturia. Diagnostic of the di.s- 

 case is the presence of the eggs, each with a 

 s]nne, in the urine. Several other species 

 occur in man, among them D. cai-nosum'' 



in death. The history as 

 moist places are subject to 

 of epidemics. Thus in the 



Fia. 237. — Btlharzut hceniittnbia. 

 Female in the gyntecophoral 

 canal ic) of the male; s\ ,s", 

 anterior and posterior suckers. 



" and D. ivestermaiui/* in 



