100 ILLINOIS BIOLOGICAL MONOGRAPHS [380 



EXPLANATION OF PLATE 



POLYSTOMA MEGACOTYLE 



Fig. 22. Entire specimen, ventral view. X 27. 



Fig. 23. Cross section of body thru ovary and uterus. X 60. 



Fig. 24. Cross section of body thru vaginae and anterior part of the testis. X 60. 



Fig. 25. Cross section thru the pharynx near the posterior end. X 85. 



Fig. 26. Cross section of seminal vesicle and cirrus sac. X 140. 



POLYSTOMA CORONATUM 



Fig. 27. Entire specimen, ventral view. X 27. 



