400 FRANK E. BEDDARD. 



The distal section of the nephridium where it traverses the 

 circular muscles is somewhat wider than the rest, and is lined 

 by a single layer of small, delicate cells ; the duct in this region 

 is inter-cellular. Occasionally the distal section of the 

 nephridium is branched (fig. 2 b) and opens by several (three) 

 distinct orifices. 



In the anterior region of the body the nephridiopores of 

 each segment are more numerous ; they could be easily ob- 

 served by a simple examination of the cuticle, and lie between 

 the setse in a more or less regular row. There were over 

 one hundred apertures in each of several segments 

 that I examined in this way. 



In transverse sections the nephridial tubules were seen to 

 pass through the body wall, not only in the immediate neigh- 

 bourhood of the seta (fig. 1), but elsewhere. Very constantly 

 the nephridial tubule did not open by a single pore, but 

 branched, at the junction of the circular and longitudinal 

 muscles, and opened on the exterior by a number of distinct 

 orifices (fig. lb). This branching of the nephridial duct 

 within the substance of the body wall is paralleled in the case 

 of Capitella, where Fischer (8) has recorded a similar 

 branching. 



Fig. 15 represents a diagram of what I believe to be the 

 arrangement of the nephridia in one of the posterior segments 

 of A. multiporus ; it maybe compared with fig. 14, which is 

 a corresponding diagram of Perichseta. I am not able to 

 give a satisfactory diagram of the anterior part of the body in 

 Acanthodrilus. 



Perichseta, Schmarda. 



The peculiar " tufted " condition of the nephridia in this 

 genus was first made known by Perrier, and has since been 

 commented upon by others. This appearance of the nephridia 

 led me to expect that I should find numerous nephridiopores 

 in each segment. I was, however, unable to put this suppo - 

 sition to the test, until I received quite recently a number 0£ 



