CONTRIBUTIONS TO THE ANATOMY OF EARTHWORMS. 449 
thin-walled muscular sac prolonged into a duct. I was unable 
at that time to find the opening of this duct or to determine 
definitely the nature of the bodies attached to the wall of the 
thirteenth segment ; I suggested, however, that they might be 
ovaries because of their position; as they consisted of small 
round indifferent cells not distinctive in appearance, but not un- 
like those of the immature gonad, this suggestion was naturally 
the only one that occurred tome. This supposition was greatly 
strengthened by Rosa’s discovery of a pair of similar structures 
in Teleudrilus, which are placed in an identical situation, 
and contain numerous mature or nearly mature ova. Since 
making myself acquainted with Dr. Rosa’s paper I have 
examined some fresh material, and have found that the bodies 
situated in the thirteenth segment in Hudrilus con- 
tain ripe ova, and are therefore evidently ovaries 
corresponding to those of Teleudrilus. These bodies in 
Teleudrilus are contained in a sac, which is continued into 
a narrow tube, which communicates with the receptaculum 
ovorum in the fourteenth segment. The wall of the sac and of 
its narrow prolongation is extremely delicate, but in the 
narrow tube the cells lining the lumen are aggregated here and 
there into heaps. All these facts appear to point to the con- 
clusion that the sac and tube which connects it with the recep- 
taculum ovorum are merely specialised portions of the celom, 
in fact a prolongation forward of the receptaculum ovorum 
which has involved the ovary. Dr. Rosa does not figure the 
details of the structure of this sac and its duct, but I should 
imagine that the aggregation of cells in the latter are similar 
to the aggregations of peritoneal cells which occur in. other 
parts of the celom (for example, in the “ pericardium” of 
Deinodrilus (8) and Megascolides (87%) ), 
Now, the sac which involves the ovary of the thirteenth 
segment in Eudrilus clearly corresponds to the sac involving 
the ovary of Teleudrilus. In Teleudrilus this-sac, as 
Rosa points out and figures, contains a portion of a nephri- 
dium. I have not found this to be the case with Eudrilus, 
but this difference does not, of course, invalidate the compari- 
