CONTRIBUTIONS TO THE ANATOMY OF EARTHWORMS. 4055 
on the evolution of the genera of Earthworms. I merely give 
instances which occur to me as representing a number of 
stages; these may evidently from their nature have taken 
place simultaneously along a number of different lines of 
descent ; they are not sufficiently complicated to lead to the 
assumption that they can only have occurred once. 
The different structure of the first from the second pair of ovi- 
ducts, together with the relations of the anterior ovarian sac in 
Teleudrilus, suggests another view, which is: that the 
anterior pair of oviducts in Eudrilus are of a different nature 
from the second pair and from those of other Earthworms, and 
represent a pair of coelomic sacs opening by a pore on to the 
exterior. In this case the relationship between these oviducts 
and the second pair would be analogous to that which the ovi- 
ducts of Teleosteans bear to those of Elasmobranchs, &c., 
among Vertebrates. 
While the structure of the adult compels me to regard this 
as a possible alternative, I do not think that the study of the 
development of the parts in question will be at all likely to 
confirm this view. 
There is therefore, I submit, no doubt that there are in 
Eudrilus two pairs of ovaries and two pairs of ovi- 
ducts which are continuous with the ovaries and 
which open in common with the spermatheca by a 
common aperture one on each side of the body. The 
fact that both pairs of oviducts open by one pore, with which 
is also connected a receptaculum seminis and a glandular 
appendix, suggests a comparison with the corresponding organs 
in the Planarians, from which group I am disposed (following 
Lang) to derive the Annelids. If this resemblance be a real one, 
it follows that the female reproductive organs of Kudrilus 
present the most archaic form which has yet been met with in 
the Oligocheta ; and that this is an ancient type of Oliochet is 
also confirmed by the structure of the efferent part of the 
male organs of generation as I have attempted to show else- 
where. On the other hand, the nephridial system and the sete 
must be regarded, if my view that a diffuse and irregular 
