378 MOORE. 



Fig. 30a represents the same region of a young worm (2 mm. long) but is 

 somewhat more enlarged. 



Fig. 31. B. illuminatus. The section of a post-genital nephridium corre- 

 sponding to the above and represented under a similar magnification. 



Figs. 32a, 32b. B. philadelphicus. Two successive sections of the efferent 

 tubule at point of entering the body-wall. X 500. 



Lettering as in Fig. 27. 



Fig. 33. B. philadelphicus. Portion of a horizontal section of somite III 

 showing the position of the efferent tubule in the spacious intermuscular space. 



X 1X2. 



eg, chlorogogue cells. 



et, efferent tubule. 



t, funnel. 



Ime, external layer of longitudinal muscles. 



Imi, internal " " " " 



/, peritoneal supports of nephridium. 



Fig. 34. B. illuminatus. Portion of a living tubule of the short loop, showing 

 nucleus, cilia, and granules contained in the protoplasm. X 880. 



Fig. 35. B. illuminatus. Section across a tubule of the short loop. X 900. 



Fig. 36. B. illuminatus. Portion of the two living tubules of the long loop, 

 showing the ciliated chambers side by side. X 500. 



Fig. 37. B. illuminatus. Longitudinal section of a ciliated chamber of the 

 long tubule loop. X 900. 



Fig. 38. B. illuminatus. Transverse section of a ciliated chamber of the 

 long tubule loop. X 900. 



Fig. 39. B. illuminatus. Optical section of one of the connecting tubules of 

 the plexus region. X 500. 



