OLIGOCHAMTA OF TROPICAL EASTERN AFRICA. 225 
to the principal nerve. I have in many cases followed out 
these ducts to the dorsal mid-line. I am inclined to believe 
that there is a connection between those belonging to the 
nephridia of opposite sides of the body. In any case the con- 
nection below the nerve cord seems to exist, the duct as it 
enters the circular muscular layer dividing into a right and 
left half. The arrangement of the nephridia of this worm is 
very similar to that which characterises the genus Libyo- 
drilus, but in Libyodrilus there are not only numerous 
branches of the circular ducts which lead to the exterior, but 
numerous branches which lead in other directions, thus form- 
ing a plexus of tubes within the body-wall. In the present 
species I did not observe anything of the kind. In one case lL 
found a branch apparently leading to the exterior. Such 
branches cannot, I am convinced, be very numerous or they 
would have been more obvious; on the other hand, fine tubes 
would be very difficult to detect without a special mode of 
demonstration, and it seems likely that the present species 
has more resemblance to Libyodrilus than I have at present 
been able to discover. 
The vascular system has not been studied in great detail. 
In the intestinal region the dorsal vessel gives off three pairs 
of branches in each segment. The vessel itself lies upon the 
chloragogen cells, and is covered superiorly by a layer of thin 
cells, which are not continuous with those of the intestine. 
Here and there are delicate muscular strands, two or three 
fibres wide, attaching the dorsal vessel to the intestine ; they 
pass from the muscular layer of one to the muscular layer 
of the other. There are six or seven of them on each side 
in each segment. The openings into the dorsal vessel of the 
branches are guarded by valves. ‘Two pairs of vessels supply 
the intestinal walls, the third pair spread out over the septum. 
Reproductive organs.—Unfortunately there was only a 
single specimen out of the ten or a dozen examples collected 
for me that was sexually mature. In this individual the gene- 
rative organs were dissected, parts of them being investigated 
later by the section method. 
