674 
Proceedings of the Royal Society 
The ovary is a rounded gland, somewhat flattened from above 
downwards ; in transverse sections it has a reniform outline illus- 
trated in figs. 3, 4; from the lower surface of the organ (fig. 3) arises 
the oviduct, which is at first ( d ) thin- walled with a wide lumen, and 
afterwards ( c ) acquires a thicker muscular coating ; the oviduct is 
everywhere lined with a single layer of columnar epithelial cells. 
In the figures referred to (figs. 3, 4) it will be seen that the 
oviduct is completely continuous with the ovary ; its lumen passes 
into the interior of that organ, and its muscular walls pass without 
a break into the muscular tunic of the ovary. 
In fig. 4 I have sketched a highly magnified section of the ovary, 
in order to display its structure as fully as possible. 
As already mentioned, M. Perrer has briefly described and figured 
the ovaries of Eudrilus , and has called attention to the fact that 
these structures cannot be interpreted in any other way, since they 
■contain most unmistakable ova entirely like those of other Lum- 
bricidse. 
In fig. 5 is represented an ovum with its germinal vesicle and 
germinal spot. The ovum is bounded externally by a very con- 
spicuous and comparatively thick membrane, which in my pre- 
parations has been rendered more distinct by deep staining with 
borax carmine ; the protoplasm of the ovum is uniformly granular, 
though occasionally I have observed cavities free from granules. 
The germinal vesicle is large, and distinctly limited by a membrane ; 
it lies usually eccentrically, and is oval or more irregularly curved 
in form; the germinal vesicle appears to contain a fluid substance, 
and has usually a single, spherical, highly refracting, germinal 
spot ; I have noted as many as three of these in some ova. In the 
figure which illustrates the ovum (fig. 5), the membrane which 
bounds it externally is represented as being homogeneous, it appears 
from my sections that there is only this vitelline membrane and no 
other. The protoplasm of the ovum forms a somewhat denser layer 
just beneath the membrane, which is better shown in fig. 5, a. 
The mature ova were in every case surrounded by a very distinct 
columnar follicular epithelium, and the rest of the compartment was 
filled up with a mass of small rounded cells (fig. 4), some of which 
were larger than others, and appeared to be ova in course of develop- 
ment ; the exact disposition of these masses of cells I am unable to 
