18 ART. 4. — EKITARO NOMURA : 



my own observations there are two main masses, an anterior 

 and a posterior. The canal takes a long convoluted course in 

 the anterior mass, and then leaves it for the posterior mass, in 

 which it again undergoes manifold convolutions. On leaving the 

 posterior mass, the canal becomes larger and finally opens to the 

 exterior. Tn the posterior segments the course of the nephridial 

 canal is simpler and the two masses are united into one. The 

 club-shaped peritoneal cells are found very rarely, so that the 

 organ never assumes a racemose appearance. 



In each segment that contains the nephridia, numerous 

 parieto -visceral muscle fibres run between the visceral organs .and 

 the body wall. They are attached to the circular muscle layer 

 of the body wall at about the end of the first third of the seg- 

 ment and in the same longitudinal line with the nephridial 

 funnel. The parieto-visceral muscle fibres are always united into 

 bundles which diverge in several directions. Some of them are 

 attached to the intestine, the ventral nerve cord and, in segment 

 VIII, also to the heart, but the remaining bundles are attached 

 to the nephridia at " the convoluted portion of the nephridial 

 canal lying outside the main mass " (Hatai). In the anterior 

 nephridia these muscular bundles are always attached to the 

 dorsal end of the racemose portion. 



The nephridial canal is intracellular throughout. The cilia 

 are not visible in preserved materials, except in the funnel, but 

 in life they are seen vibrating rapidly. 



The nephridial cells have a more or less dense cytoplasm 

 containing granules of different sorts. Some of them are exactly 

 similar to those which are found in the cœlom. This fact was 

 regarded by Schneider as proving the phagocytic action of the 

 nephridial colls. These granules are also found in the peritoneal 

 and seta-forming cells and often in the ganglion colls. These 

 facts appear to me to throw some light upon the fate of the 

 cœlornic granules. 



The main masses of both forms of nephridia consist of peri- 

 toneal and nephridial cells mixed together. 



The nephridial coils may be entirely destitute of a cell wall 



