338 FRANK E. BEDDARD. 
but in Branchiura, instead of receiving the vas deferens, as 
it does in the two genera mentioned, this organ forms a diver- 
ticulum of the vas deferens. The difference is in fact precisely 
analogous to that which exists between Eudrilus and Ponto- 
drilus. A tubular gland exists in both: in Eudrilus the 
vasa deferentia open into it; in Pontodrilus they open at its 
base into a duct leading from it. In the latter case there is no 
valid reason against regarding the two structures as homologous, 
and I am of opinion that the glandular sacs of Branchiura 
which have just been described represent a portion of the 
atrium. This glandular section of the atrium passes abruptly 
into a narrow tube (@ in fig. 1), which receives the sperm- 
duct just at its commencement: the sperm-duct becomes ex- 
ceedingly narrow just before it opens into this tube, which, 
like the sperm-duct, is ciliated. The distal part of the atrium, 
at first ciliated, loses the cilia further down, and the character 
of the lining epithelium abruptly changes: the cells become 
taller, and the cellular membrane as a whole is thrown into 
folds. Both regions of the tube are enveloped by a thick mus- 
cular coat, but the most distal portion is probably protrusible, 
since it is surrounded by a space, which is, I think, as in 
Tubifex, &c., lined by epitheliunn. The male efferent appa- 
ratus of Branchiura differs, therefore, in a number of points 
from the corresponding structures of other Tubificide. The 
division of the atrium into two parts is commonly seen in the 
Tubificide, and is particularly well marked in Bothrio- 
neuron Vejdovskyanum,! but in no Tubifex is the glandu- 
lar part so greatly developed, nor is there any other genus in 
which the vas deferens joins the muscular part of the atrium, 
thus making the glandular partinto a cecum. This particular 
relation of the two parts of the atrium to the vas deferens is 
common among earthworms. 
The spermathece lie in Segment 10. They are more or 
less pear-shaped, narrowing towards the external opening. 
They have no ceca or glandular appendages of any kind. 
They contained spermatozoa not aggregated into bundles. 
1 Stole, loc. cit., Taf. iv, fig. 7, zchv and ad. 
