326 



ERNEST CARROLL FAUST. 



the collecting tubules arrange themselves in anterior and pos- 

 terior branches. 



The first xiphidiocercaria in which the writer was able to 

 make an analysis of the number and relation of flame cells was 

 Cercaria isocotylea Cort (Faust, iQiSa; also Fig. 3, this paper). 



3 45 



FIG. 3. Cercaria isocotylea Cort, ventral view, showing excretory system and 

 mucin glands. X 170. 30, stylet, X 540. 



FIG. 4. Cercaria candelabra nov. spec., ventral view, showing excretory and 

 digestive systems. X 170. 40, stylet, X 540. 



FIG. 5. Cercaria trifurcata nov. spec., ventral view, showing excretory and diges- 

 tive systems. X 105. 50, stylet, X 540. 



The number of flame cells is large for a cercaria and the arrange- 

 ment is complex. Placing the cells of this species into anterior 

 and posterior groups respectively, the flame-cell formula is 



22 = ([2 +2+3 + 3 + 3+ 3l + [2 +2+ 2]). 



More recently the writer has studied the excretory system in 

 two xiphidiocercariae, also from Urbana, Illinois, C. trifurcata 



