ee 
Davaineid Cestode from a Wallaby. 607 
trunk is situated about midway between the ventral excre- 
tory vessel and the inner margin of the cirrus-pouch ; it 
may, however, approach and lie close to the excretory vessel. 
On the aporal side the nerve-trunk lies in close proximity 
to the ventral excretory vessel. The course of the nerves in 
the head region was not followed. 
(d) Genital Organs (figs. 3 and 4).—Each mature seg- 
ment possesses one complete set of male and female genitalia, 
with their genital pores close together and unilateral in 
position. 
These pores are in the anterior third of the segment, and 
are situated on a slight eminence. Hach eminence is over- 
hung by the projecting posterior angle of the segment 
preceding. 
The genital rudiments of the ovaries are the first to appear 
Mature segments, slightly flattened. 
(Magnification about 40.) 
N.=nerve-cord; Ov.=ovary; Sh.G.=shell-gland; 7.=testes; V.D.= 
vas deferens; V.#,C.=ventral excretory gland; Y.G.=yolk- 
gland. 
about 8 mm. from the anterior end; some mms. further 
down the vagina begins to develop, to be soon followed by 
the vas deferens. The rudiments of the testes appear very 
much later, their first indications being at about 40 mm. 
from the anterior end. Mature segments are found about 
5 mm, further down. 
All the genitalia are confined to the central third of the 
parenchyma, being bound dorsally and ventrally by the thin 
sheet of transverse muscles and laterally by the ventral 
excretory canals. 
The male organs consist of about 50 rounded testes, about 
65 « in diameter, arranged in two groups separated by the 
ovary. ‘The larger group, which consists of about three- 
fourths of the number of testes, is situated aporally. The 
testes do not pass laterally over the ventral excretory canal. 
