A NEW BRANCHIATE OLIGOCHAITE. 339 
The ovaries, as already mentioned, lie in the 11th segment. 
In the sexually mature worm I found masses of developing 
ova in Segments 12 and 138; in the latter segment they were in 
close contact with the sperm-sacs, and appeared to be enve- 
loped in a common sheath. In Segments 18 and 19 were two 
or three fully mature ova, which, as in most aquatic worms, are 
of large size, and are filled with spherical yolk bodies. 
For a long time the existence of oviducts in the Tubificidee 
was unknown, and the ova were believed to leave the body in 
some way through the penis sheath. These structures were 
first found by Stole in Ilyodrilus and Psammoryctes, and 
subsequently by myself in Clitellio and Hemitubifex.'’ I 
have found them in Branchiura, where they are of precisely 
the same structure as in other Tubificide. 
Affinities. 
It will be apparent from the above account that Bran- 
chiura must be referred to the Tubificide, of which family, 
however, it forms a very distinct new genus. It is difficult to 
say to which of the remaining genera of the family it comes 
nearest ; it is, indeed, nearly equally remote from all. The ab- 
sence of prostates (‘‘ Cementdriisen’’), as well as the presence 
of the integumental network of blood-vessels, perhaps brings 
Branchiura into nearer proximity to Ilyedrilus than to any 
other Tubificide. Stole has shown how Ilyodrilus connects 
the Tubificide with the Naidomorpha ; but the relationship of 
the Tubificide with the higher forms is not yet clear. I may 
point out, therefore, that the glandular part of the atrium in 
Branchiura shows in its structure a certain amount of re- 
semblance to that of the Lumbriculide (Rhynchelmis), and 
to that of the simply organised earthworm Moniligaster. 
Its relations to the vas deferens are unlike what occurs in any 
of the lower Oligocheta, but are paralleled in many earth- 
worms (e.g. Pontodrilus, Cryptodrilus). 
It is impossible at present to distinguish generic from 
1 « On Certain Points in the Structure of Clitellio” (Claparéde), ‘ Proc. 
Zool. Soc.,’ 1888, p. 485. 
