1920.] R. B. Seymour Seweli. : Mesocoelium sociale. 



91 



Fig. 4. — The excretory system of Mesocoelitim sociale (Liihe). 



acct., accessory collecting tube ; act., anterior collecting tube; b., excretory 

 bladder; cc^, common collecting tube ; e-r/)., excretory pore ; O'z;., ovary; /irf., pos- 

 terior collecting tube ; t., testis. 



On the left side of the figure the three anterior accessory collecting tubes are 

 shown * and the three posterior tubes f . 



