NEW SPECIES OF OCNERODRILUS. 237 



The main vessel in the pouch (fig. 20, iv. v.) branches 

 in several parts close to the entrance of the pouch, the 

 various vessels running longitudinally and parallel to the 

 distal end. These vessels group themselves into about 

 six bunches (fig. 20), and throughout the greater length 

 of the pouch the vessels of each branch keep together, 

 forming elevated, longitudinal and parallel ridges, which 

 encroach on the upper but especially on the inner surface 

 of the pouch. On the inner surface these ridges are 

 prominent and sometimes so large as to almost divide the 

 pouch in several parallel chambers. No such division 

 takes place, however, the inner large cavity being only 

 one. At the distal end these ridges come together, and 

 the inner cavity ends between them in various narrow 

 sinuses, one each between two ridges (figs. 19 and 12). 

 These sinuses continue forward and again unite with an 

 inner system of lacunary cavities (fig. 12, /. /.) very much 

 as is the case in the pouch of Gordiodrilus, as described 

 by Beddard. In that genus these cavities connect with 

 the nephridium through a narrow tube. In none of the 

 sections I made of Ocnerodrilus could I find with cer- 

 tainty a similar arrangement, but I am strongly inclined 

 to believe that one really exists, as close to the concave 

 side of the outer wall of the pouch I frequently found a 

 comparatively broad tube with a clear and large, glandu- 

 lous lumen which seemed to end on the outside of the 

 pouch near its distal end, just opposite to where the inner 

 cavities begin. A possible connection with the nephri- 

 dium I could not establish. The inner lining of the pouch 

 is ciliated and very thin. It is strongly striated, consist- 

 ing of flattened cells with round nuclei. This striation 

 is also seen in the lining of the inter-lacunary cavities, 

 but not in the inter-vascular tissues in which the blood 

 vessels are imbedded. The nuclei are of the same form 



