THE LEECHES OF MINNESOTA 51 



cells ("Kronenzellen", Graf, '99) and a short stile cell which opens 

 into the larger receptaculum. 



In conclusion I wish to acknowledge my great indebtedness to 

 Professor Nachtrieb, under whose direction this work was done, 

 for his kindly assistance and many valuable suggestions ; and to the 

 Alumni Association of the University of Minnesota for fellowship 

 privileges enjoyed during the year 1903-4. 



