I9g10.] J. STEPHENSON: Aquatic Oligocheta of the Punjab. 67 
1909. The animals were present in one of the tanks in consider- 
able numbers, along with Cheiogaster orientalis; and a fair propor- 
tion of both species were in a condition of sexual maturity. For 
the sake of completeness I have incorporated in the present 
account a certain number of the facts recorded in my earlier paper. 
Both sexual and asexual reproduction may go on together. 
The testes are the first organs to be formed, and appear on 
examination of the living worm as homogeneous hvaline masses 
attached to the posterior face of septum 4/5. The sperm-morulz 
ripen in the vesicula seminalis, but may sometimes be seen in the 
body-cavity of the anterior part of the animal, as far forwards as 
the third or even the second segment; and I have previously 
noted that slight violence may cause spermatozoa to be discharged 
through a rupture of the body-wall at the tiv of the prosto- 
mium. . 
The vesicula seminalis, or sperm-sac, forms early, and is 
properly (plate viii, fig. I) an extension of septum 5/6; later it 
becomes much dilated, extending backwards through the sixth, 
seventhand eighth segments, and finally may even reach the tenth. 
The relations of the funnel of the vas deferens will be under- 
stood after reference to fig. 1. The mouth is turned backwards 
into the sperm-sac; it is of fair size, and the lip of the funnel 
appears in some specimens to be much prolonged on one side 
(apparently not always the same side), so that the plane of the open- 
ing is very oblique. The tube is fairly broad, and is lined by cells 
of approximately cubical shape ; it at first passes vertically down 
along the septum, then takes one or two bends, but is not coiled. 
It opens by a rather wider portion into the atrium, on the anterior 
face of the latter, a little below the middle of its height. Its more 
or less horizontal portion is surrounded by prostatic cells, in two 
or more layers. The atrium is approximately spherical, is lined 
by cells which are a little higher than broad, and has only a thin 
external muscular coat. The passage to the exterior is short, and 
opens into a shallow funnel-shaped depression of the surface; the 
passage and funnel-shaped depression are lined by columnar cells. 
On a surface view of the animal these depressions are distinguish- 
able as clearer spaces in the opaque clitellum. 
The ovaries form soon after the testes, and are attached to 
the posterior face of septum 5/6. The ovisac is a diverticulum of 
septum 6/7 ; its relations may be seen in fig. 1. The sperm-sac is 
included within it, and the ova lie as a rule behind the sperm-sac, 
sometimes as far back as segment x; they may however lie on one 
side of it, so that some sperm-morule or spermatozoa may occupy 
a position posterior to that of the ova. Eggs are seen in various 
stages of development; in their later stages they accumulate within 
themselves an enormous amount of yolk-matter ; I did not in my 
former paper recognize how enormous (for so small an animal) this 
aggregation of yolk might be (y, fig. 1; a much larger mass is 
shown in fig. 21 of my previous paper) ; and I was led to describe 
it and the spherical glancing particles of which it is composed as 
