IgI2.| J. STEPHENSON: Indian Aquatic Oligochaeta. 237 
(i) The atrium and paratrium are confined to segment xi, 
and do not encroach on xii. 
(ii) The proximal part of the atrium is a spherical sac, 
sharply marked off from the middle portion, and lined by cubical, 
not columnar, epithelium (pl. xii, figs. I, 4). 
(iii) There is no bulky covering of gland cells surrounding 
either atrium or paratrium (pl. xii, figs. I—4). 
(iv) The lower portion of the paratrium runs side by side 
with the middle region of the atrium in a common sheath (pl. xi, 
fig. 2), as in Michaelsen’s specimens, but their lumina never unite, 
and open separately into the distal section of the atrium (pl. xil, 
fig. 3). 
(v) The combined atrium and paratrium undergo fewer wind- 
ings in the coelomic sac than is described by Michaelsen. 
(vi) The distal section of the atrium is straight throughout, 
not hooked at its dorsal extremity (pl. xii, fig. 5). 
(vii) The spermathecae are small, egg-shaped, with thick walls 
and small lumen. 
(viii) The female efferent apparatus is not described by 
Michaelsen Beddard describes an oviduct opening on the furrow 
between segments xi and xii. I find an ovarian funnel on septum 
11/12 (pl. xii, fig. 1), which leads to the exterior by a short oviduct 
opening on segment xii, a little distance behind the level of 
septum 11/12. 
I think it probable that most, if not all, the differences between 
the Hamburg specimens and the present one are to be referred to 
their being in different stages of development. And since the 
present specimen is presumably at a less rather than a more 
advanced stage of development than that described by Beddard, 
and since nevertheless it shows a fairly close agreement with 
Michaelsen’s description, it does not seem likely that the dis- 
crepancies in the accounts of Beddard and Michaelsen are due to 
differences in the degree of maturity of their respective speci- 
mens. ‘The explanation of those discrepancies is therefore to be 
sought in one of the other directions indicated by Michaelsen. 
GCE 
Limnodrilus socialis, Stephenson. 
The above worm was recently described by me (13) from 
Lahore, where it is common. I have twice received specimens 
alive from Mr. Gravely of the Indian Museum; the first occasion 
was in March ror1, the worms having been taken in a masonry 
drain at Belgatchia near Calcutta, the second in May 1911, when 
a tube of these worms, taken within the precincts of the Museum, 
was received at the same time and under the same conditions as 
he Branchiura sowerbyt previously mentioned. 
Since the shape of the cerebral ganglion is largely used for 
purposes of discrimination and identification, I append a sketch 
of it, from a specimen in which it was well seen (fig. 4). 
