OLIGOCHATA OF TROPICAL EASTERN AFRICA. 245 
fact, any one acquainted with this group of worms would pro- 
bably assign the species from its general appearance to the 
Lumbriculide or perhaps to the Tubificidee. 
Reproductive organs.—The testes are a single pair 
only, which are placed in the 10th segment attached to the 
front wall of that segment. There appear to be no actual 
sperm-sacs, but the 10th and the Lith segments are filled with 
a mass of developing sperm. ‘This is so compacted together 
that the appearance of a definite sac is produced, and the 
sperm is so abundant and occupies so much of the interior of 
the two segments in question that the septum dividing them, 
which is thinnish, is hardly visible without a very careful 
inspection. 
The funnels of the sperm-ducts correspond in number to 
the testes, that is to say there is only a single pair, which les 
opposite to the testes in the same segment. They are much 
folded. 
The terminal apparatus of the male efferent duct is formed 
by an atrium. 
The atria (fig. 5) extend through more than one segment, 
and are long enough to be coiled. They open on each side 
on the 13th segment, the aperture being lateral in position, 
showing therefore, which is remarkable, no relation to the 
pores of the spermatothece. The tubular atria have, however, 
not a close resemblance in structure to the tubular atria of 
such generaas Acanthodrilus. Their structure is as follows: 
—The internal lining of the tubes is formed by a single layer 
of cells, which have a clear appearance, as they were not 
stained by a long immersion in borax carmine. The cells 
were certainly in some places ciliated. Towards the external 
pore these lining cells got to be more and more like the epi- 
dermic cells, and were also ciliated, until at the actual orifice 
they became continuous with the epidermis. Outside the epi- 
thelium is a layer of muscular fibres of some thickness. These 
fibres are entirely circular in disposition. They do not form 
an absolutely continuous covering of the epithelium; here 
and there slight gaps are to be seen. These gaps correspond 
