106 ILLINOIS BIOLOGICAL MONOGRAPHS [324 



PLATE IX 



Fig.36-42. Inclusive. Consecutive 20 micra sections of oral sucker, Cydocoelum halli. X71. 

 Fig. 43. Cross section of oral sucker, Cydocoelum pseudomicrostomum. X90. 

 Fig. 44. Cross section through anterior portion of oral sucker, Cydocoelum dongatum. X90. 

 Fig. 45. Cross section through genital atrium, Cydocoelum elongatum. Xl2. 

 Fig. 46. Frontal section, Cydocoelum elongatum. X105. 



Figs. 47 & 48. Cross sections of oral sucker of Cydocoelum elongatum, posterior to that in 

 figure 44. X90. 



