6 
Tapeworms from Ostrich 
structure. It runs diagonally nearly to the anterior border of the proglottis 
and at approximately two-thirds of its length makes a right-angled turn 
towards the dorsal surface. The cirrus is short, uncoiled, and unarmed, and 
opens into the vas deferens while still only half-way along the cirrus-sac. 
' After a few coils which fill up the remainder of the cirrus-sac, the vas deferens 
emerges from the inner extremity and extends as a coiled duct along the 
antero-dorsal surface of the proglottis to a point half-way between the ex¬ 
cretory vessels, there splitting up into the vasa efferentia. The testes are 
numerous, approximately 200 in number and of normal size. They fill the 
whole dorsal surface of the proglottis, extending laterally to the longitudinal 
excretory vessels, but with fewer on the poral side than on the aporal. In 
the centre of the proglottis, the layer is two or sometimes three testes deep, 
towards the lateral margins only one deep. 
The vagina is devoid of a sphincter muscle. It runs posteriorly to 
the cirrus-sac and then proceeds transversely across the proglottis, mid¬ 
way between the dorsal and ventral surfaces, passing the excretory vessels. 
At one-third of the proglottis breadth it opens into the receptaculum 
seminis. This latter is a narrow thin-walled tube gradually decreasing in 
diameter as it approaches the centre of the proglottis. It is always chokecl 
with spermatozoa. The ovary is a comparatively small but very much 
lobed gland, lying on the ventral surface of the proglottis with the lobes 
directed towards the dorsa] surface; its ventral aspect is flat. It lies 
ventral and slightly posterior to the inner end of the receptaculum seminis. 
Posteriorly to it and of a slightly smaller size is the yolk-gland. This is 
bilobed, with the two lobes united by a narrow bridge from which springs 
the vitelline duct. It is more compact than the ovary. The shell-gland is 
in the form of a sphere of cells united at their inner extremities and grouped 
round the oviduct, and lies upon the dorsal surface half-way between the 
yolk-gland and ovary. Inside it the oviduct coils slightly before receiving 
the vitelline duct. A definite but ephemeral uterus is developed, lying trans¬ 
versely across the proglottis, anteriorly to the female glands and inserting 
itself among the testes on the dorsal surface. It never passes beyond the 
stage of a small tube, slightly enlarged where the oviduct joins it, and quickly 
breaks up into egg-capsules, approximately 140 in number, which fill the whole 
proglottis, extending laterally beyond the longitudinal excretory vessels 
(Text-fig. 2). Each capsule usually contains six eggs, and is polygonal in 
shape owing to compression by its neighbours. The interior (Plate I, fig. 6) 
is filled with a fibrous mass in which the eggs are embedded and which 
is further partially sub-divided by a dark homogeneous substance similar 
in appearance to the capsule wall. There is no tendency to isolate separate 
eggs in the capsule, the partial compartment formed sometimes containing 
several eggs and sometimes being empty. Also no case could be seen in 
which the eggs appear each in a separate capsule or scattered through the 
parenchyma as in other species of Davainea. The capsule is far too definite 
