CONTRIBUTIONS TO THE ANATOMY OF HKARTHWORMS. 453 
theca might therefore easily have shifted the ovary from its 
original position. 
I am inclined therefore to adhere to my original opinion 
that the mass of cells containing developing ova which is 
attached to the anterior wall of segment xiv is really an 
ovary; but I agree so far with Dr. Rosa—and indeed I 
have already put forward this view—that the walls which 
enclose the ova, and from which partitions grow inwards 
subdividing its cavity, are very probably to be regarded as the 
receptaculum ovorum. ‘The receptaculum ovorum has here 
grown round the ovary just as the sperm-sacs frequently 
enclose the testis. 
Returning now to the oviduct which is connected with the 
ovary of the thirteenth segment and which also communicates 
with the duct of the spermatheca, is this structure homologous 
with the tube which in Teleudrilus connects the ovary with 
the receptaculum ? The homology cannot be a complete one, 
so far as can be determined from the minute structure and 
relation of the parts in question. The said tube in Teleu- 
drilus is a celomic sac, perhaps produced by a growth from 
the receptaculum ovorum of segment xiv, perhaps an indepen- 
dent outgrowth of the wall of segment x111 which has become 
fused with the former. The tube in Eudrilus is probably a 
compound structure. The part which immediately surrounds 
the ovary is no doubt to be looked upon as a ccelomic sac 
corresponding to that of Teleudrilus. This sac passes 
without any break into a tube with a lining of cubical 
epithelium opening into the spermatheca. I am inclined to 
think therefore that this tube may be also celomic in origin, 
but the aperture into the spermatheca may be formed by an 
outgrowth of the epidermal involution (?) out of which the 
latter has been formed. 
This is, of course, merely a supposition, and the matter can- 
not be decided until the development of this very interesting 
Oligochet has been worked out. 
The oviduct of the thirteenth segment differs in certain 
important particulars from the oviducts of segment xiv. In 
VOL, XXX, PART 4,——NEW SER. GG 
