5O WESLEY R. COE. 



summit of the ridge, whereas if the opening is between two such 

 ridges the duct is necessarily short and has a correspondingly 

 thicker epithelial lining. The length of the nephridial duct 

 must thus vary in accord with different degrees of extension of 

 the esophageal walls and the accompanying changes in the height 

 of the longitudinal ridges. 



in' 



FIG. 3. 7ieniosowa cingulatmn. Diagram of portion of transverse section of 

 body through esophageal region, showing an efferent nephridial duct (nd) opening 

 into lumen of esophagus and another (nd f ) leading to dorso-lateral surface of body. 

 Reference letters as in Fig. I. X 5- 



The nephridial system appears to be continuous throughout 

 its whole length. From the larger canals originate both the 

 ducts opening into the esophagus and those opening externally 

 (Fig. 3). The excretory fluids may be discharged in either 



