THE LEECHES OF MINNESOTA 15 



posterior third of the digestiv tract and the supporting and vascular 

 tissues of the posterior half of the body have been removd, thus 

 exposing part of the digestiv tract, part of the ventral nerve cord 

 and part of the reproductiv and excretory organs. 



In the third stage, shown in figure 3, the supporting tissues and all 

 of the digestiv tract have been removd, thus exposing the reproductiv 

 organs, the excretory organs and the central nervous system. 



The longitudinal muscles of the body wall are plainly seen in 

 each of the three figures. 



