98 ILLINOIS BIOLOGICAL MONOGRAPHS . {373 



EXPLANATION OF PLATE 



POLYSTOMA OPACUM 



Entire specimen, extended, ventral view. X 20. 



Reconstruction of genital apparatus from toto preparation and cross 



sections. X So. 

 Hook from genital coronet. X 550. 

 Frontal section thru the anterior sucker and pharynx, showing in section. 



nerve commissures and vitellaria. X 60. 

 Cross section of body thru uterus and cirrus sac. X 60. 

 Cross section of body thru the testis. X 60. 

 Cross section thru the anterior pair of bothria. X 60. 



