-^IG. 20. 



Fig. 19. 

 Fig. 19.-Cercaria of Bilharzia used in experiment, x 200 

 F.g. 20._Adult female taken from portal vein of mouse, experimentallv infected 



mouse. <K 18 (circa). 

 Pig. 21._Anterior portion of adult male taken from the same source, x 18 (eirca). 



