Contributions to a Knoivledge of South African Oligochacta — Part I. 235 
ascending posterior portion. The anterior descending moiety lies imme- 
diately behind the septum separating xi and xii. 
The sperm duct leads backwards from the funnel through the septum 
xi, xii, and becomes intricately coiled ventrally to the anterior limb and 
axis of the spermiducal gland. It then passes upwards and backwards to 
open into the extremity of the posterior ascending part of the spermiducal 
gland. 
The penis projects for some distance into the ventral moiety of the 
large chamber into which the male pore leads, and its cavity eventually 
opens into the same. 
The large chamber consists of a vertical half which is definitely marked 
off from a posterior portion which lies behind the entrance of the penis, 
and with the exception of its anterior extremity lies horizontally. This 
posterior portion lies partly in segments xii and xiii, and receives at its 
free posterior extremity the spermathecal duct. 
The penis is an elongate pear-shaped structure, its basal portion being 
attached to the anterior or antero-dorsal wall of the large sac into which 
the male pore opens. The attachment lies just where the posterior 
moiety of this sac passes backwards, and this gives at once the impression 
that this posterior part is of the nature of a diverticulum from the vertical 
portion which leads to the exterior. 
The penis resembles histologically that of Astacopsidrilus in the main, 
but the chitinous band external to the lining epithelium is absent. 
The wall of the penis is composed of three layers : — 
(a) The inner epithelium is composed of large cells, with markedly 
granular protoplasm, and with a large spherical nucleus situated towards 
the base. 
(b) The middle layer of muscle fibres becomes gradually thicker 
towards the base of the penis where it reaches its maximum. The area 
occupied by the musculature is very spongy in the basal region, but 
this may be due to post-mortem changes or imperfect preservation. 
(c) The outermost layer is composed of epithelial cells which become 
much more important gradually from the apex to the base of the penis. 
Except in the immediate region of the apex of the penis this outer layer is 
heavily folded, and resembles both in this respect and in the nature of its 
component cells the lining layer of the sac into which the penis protrudes. 
The large sac into which the male pore leads and which contains the 
penis has a wall composed of three elements : — 
(a) The inner epithelium is heavily folded, and projects into the lumen 
of the sac in the form of large blunt villi. Each villus is composed of a 
number of small squarish cells with a centrally situated nucleus. Into 
the heart of each villus there project muscle fibres which externally mmgle 
with those of the second layer. 
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