PLATE II. 



Placobdella montifera. x 4.5. 



Fig. 10. The principal features of the external morphology of the 

 dorsum of somites I-XII. Very slightly diagrammatic. 



Placobdella hollensis. x 8. 



Fig. 11. Dorsal view of the first ten somites. 



Hemiclepsis occidentalis. x 56. 



Fig. 12. Dorsal view of the first ten somites of a young example still 

 remaining with the parent, showing the annuli and the 

 eyes. 



Placobdella pediculata. x 3.5. 



Fig. 13. Ventral view of the anterior thirteen somites. 



Fig. 14. Dorsal view of the anterior thirteen somites. 



Fig. 15. The head end as seen from in front. 



Figs. 16, 17 and 18. Dorsal, ventral and lateral view respectively of 

 the posterior end, showing the annulation and the peculiar- 

 ities of the caudal sucker and its peduncle. 



