1919] 



Cort: The Cercaria of the Japanese Blood Fluke 



499 



a dorsoventral differentiation depending on the position of the ducts 

 of the cephalic glands, the mouth and buccal cavity. This dorso- 

 ventral differentiation is also clearly indicated by the shape of its 

 posterior region. That this unusual differentiation of the oral sucker 

 is probably common to all true schistosome cercariae is suggested by 

 the description of a similar differentiation of the oral sucker of 



Fig. 3. Diagrammatic representation of the excretory system of the cercaria 

 of Schistosoma japonicum, ventral view; letters as before. 



