Nephrostomes 



Glomeralits 



Pronephros 



Pronephric duct 



Glomcndi 



Mesonepkros 



. 341. THE EXCRETORY SYSTEM OF A Petromyzon fluviatili*, 22 MM. IN 

 LKMITH, from the inner side. (After Wheeler.) About half the entire 

 length of the primary urinary duct is represented, and behind the pronephros 

 it is greatly coiled. Four pronephric nephrostomes and a folded glomerulus 

 are present, and between the pronephros and mesonephros is a portion 

 wanting in tubules, 



