Explanation of Plate B 



Reproduction of fotografs of Hsemopis grandis in three stages 

 i if dissection. 



Fig. 1. Represents the leech with the body wall cut along the 

 mid-dorsal line and pind out on each side. 



Fig. 2. Represents the same leech with the supporting and vas- 

 cular tissue of the posterior half and all of the in- 

 testin removd. A small portion of the dorsal wall of 

 that part of the digestiv tract shown is cut away. 



Fig. 3. Represents the same leech with all of the digestiv tract 

 and surrounding supporting and vascular tissue re- 

 movd. The "brain", ventral nerve cord, reproducth 

 and excretory organs are easily recognizd. 



Tlie logitudinal muscles of the body wall are evident in all the 

 figures. 



