CHAPTER IV. 

 TREMATODES PARASITIC IN MAN. 



(i) Monostomidce, in which only the anterior or oral 

 sucker is present. There is no second sucker or acet- 

 abulum (fig. 5, A). The genital pore is ventral and about 

 the middle. They are usually found in the alimentary 

 canal of certain vertebrates. 



FIG. 5. Diagram of arrangement of suckers. A, Monostoma ; 

 B, Distoma or Fasciolidse ; C, Paramphistoma. 



In man the Monostoma lent is, of which immature forms 

 have once been found in the lens of the eye, is the only 

 known representative, and it is doubtful if this is not the 

 young form of some other parasite. 



The other families have both the oral sucker and a 

 second sucker or acetabulum. There are three families 

 represented in man : 



(2) Fasciolidce, in which the second sucker is ventral, 

 not further removed from the oral sucker than the middle 

 of the body (fig. 5, B). 



(3) Paramphistomida $ in which the second sucker is 

 at the posterior end of the body (fig. 5, C). 



(4) Schistosomidce. The male and female forms are 

 separate individuals, i.e., they are not hermaphrodite. The 

 second sucker is ventral and near the oral sucker. 



