644 



a comparison of Dr. Rosa's paper with my own. In my paper I de- 

 scribed and figured a pair of problematic bodies in the 1 3 *'' segment 

 which are contained in a muscular sac prolonged into a duct lined 

 with epithelium. I was unable at that time to find the opening of this 

 duct; I have now ascertained that it communicates with the duct of 

 the spermatheca close to the opening of the glandular body attached 

 to the latter. 



I regarded the bodies attached to the anterior wall of the 1 3''' seg- 

 ment as being probably ovaries, although they consisted only of small 

 cells uniform in size and not distinctive in appearance; this suppo- 

 sition is greatly strengthened by Rosa's description of a pair of simi- 

 lar structures^, which are placed in an identical situation in Telcu- 

 drilus and contain nearly mature ova. These bodies in Tdeudrilus are 

 contained in a sac which is prolonged into a duct communicating with 

 the receptaculum ovorum in the 14*'' segment. The wall of the sac and 

 duct are extremely delicate, but in the duct the cells lining the lumen 

 are aggregated here and there into heaps; all these facts appear to point 

 to the conclusion that the sac and duct are merely specialised portions 

 of the coelom, in fact a prolongation forward of the receptaculum ovo- 

 rum which has involved the ovary. Dr. Rosa does not figure the details 

 of the structure of the sac and duct, but I should imagine that the 

 aggregations of cells in the latter are similar to the aggregation of peri- 

 toneal cells which occur in other parts of the coelom." 



Now the sac which involves the supposed ovary of the 13*^'' segment 

 in Eudrilus clearly corresponds to the sac involving the ovary of Tcleu- 

 drilan. Dr. Rosa suggests that the duct also corresponds, and opens 

 into the receptaculum; I must admit that his suggestion, based upon 

 the very imperfect description which I gave of this part of the repro- 

 ductive system, is not unreasonable. Now however that I am able to 

 record that the duct in question is lined by a single layer of 

 columnar cells and opens into the duct of the spermatheca, 

 it is no longer possible to compare the tAvo structures. The tube by 

 which the ovary of the 13*'' segment in Eudrilus communicates with 

 the exterior is a real duct, while the tube which leads from the ovary 

 to the receptaculum in Teleudrilus is simply a coelomic sac. 



I now come to the question of the receptaculum ovorum in the 

 two genera. Does the structure which Rosa calls by this name in 

 Teleudrilus represent what Perrier, Horst, and myself have called 

 »ovary« in Eudrilusl Rosa found that the oviducts of Teleudrilus, al- 

 though opening separately on to the exterior and not in common with 



5 I have since found numerous mature ova in these bodies in Eudrilus. 



