University of Michigan 



PLATE I. 



(All drawings made with the aid of the camera lucida.) 



Figure I. Cercaria marcianac, ventral view, drawn from whole 

 specimen on slide No. 150. 



Figure 2. A group of Cercaria marciaitae as they occur under the 

 mesentery of heavily infested snakes. Magnified. 



Figure 3. Cercaria vegrandis, ventral view, drawn from whole 

 specimen on slide No. 155. All structures are shown much more dis- 

 tinctly than in the preparation. 



Figure 4. Detail of posterior end of Cercaria vegrandis. This 

 specimen is somewhat more mature than the one shown in figure 3. 

 Note especially the second mass of cells. Drawn to the same scale as 

 figure 3. 



