The flow of fluid in the protonephridial canals of Hymenolepis diminuta

Abstract

1. 1. Two types of activity were observed in Hymenolepis diminuta. The more common peristalsis is superseded by rapid ripples as the pCO 2 is increased. 2. 2. Fluid flow in the protonephridial canals in turn depends upon these activities. 3. 3. The pressure exerted by the fluid in the canals and the volume of these canals were measured. 4. 4. The mean rates of excretion of lactate, urea and ammonia were calculated as 19·4, 1·02 and 0·08 μg/mg dry wt. per hr respectively. It is probable that the canals are the main excretory route for lactate and urea.