31 



3- Redia of Distoma. (Low power.) Pharynx; contained Cercariae. 

 4. Cercaria under high power, with suckers and tail. 



TREMATODA 



5. Polystoma integerrimum from frog's bladder. (Simple lens.) Mouth on anterior sucker; 

 disc with circle of suckers at hind end of ventral surface; two lateral papillae. 



