NEW AVIAN CESTODE. 411 
The number of testes varies between 7 and 9, but the most 
usual number is 8. 
The ovary is a somewhat loose and irregularly lobed organ in 
which the ova do not appear to be very closely packed. It 
occupies the greater part of the centre of the proglottides in the 
younger portion of the strobila. 
Below the ovary, and extending a little in front of it, lies the 
large, rounded vitelline gland, while above the ovary, in young 
progiottides, the uterus appears as a very narrow crescentic tube 
with conspicuous cell-nuclei, the convexity of the crescent being 
towards the head of the worm. 
In such a young segment, the genital ducts and apertures are 
difficult to separate, the common genital atrium being as yet 
imperfectly developed. 
The vagina first appears as a rather wide canal running inwards 
from the thickening on the right side, which is to be the genital 
atrium ; at first it runs a nearly straight course, with a slight 
forward inclination. It then turns backwards at an obtuse angle, 
and forms a remarkable loop, returning over itself and running 
upwards and forwards for a short distance, finally taking a sharp 
bend downwards and descending perpendicularly to the ovary. 
At the point where the backward loop of the vagina occurs, 
there is at first no perceptible enlargement of the duct, which 
appears to be of the same width throughout. But in older seg- 
ments there is in this position an expansion to form a recep- 
taculum seminis. In sections of the older proglottides this is 
always seen to occupy the space between the backwardly-directed 
‘“‘ horns” of the uterus. 
The vas deferens is, in young segments, with difficulty dis- 
tinguished from the vagina, lying as it does above it, and 
following an approximately parallel course. Later it lengthens, 
widens, and becomes very elaborately coiled, at the same time 
becoming gorged with sperm. It comes to occupy a con- 
siderable part of the right side of the segment, its coils being 
concentrated mainly towards the anterior border. 
Distally it passes into a large spherical cirrus-sac, which measures 
0:055 mm. in diameter. Within this the duct continues to coil 
about, and finally passes out on the opposite side, as the cirrus, 
or male cloacal canal, This projects into the upper portion of a 
large genital atrium, with thick muscular walls. At the point 
where it leaves the cirrus-sac, the lumen of the cirrus shows a 
considerable dilatation, which is always found to be full of sperm. 
This may perhaps be regarded as serving the purpose of a seminal 
vesicle, no other organ of that kind, apparently, being present. 
Immediately below the male cloacal canal lies the opening of 
the vagina, which passes inwards from the genital atrium, below 
the cirrus-sac, curves upwards behind this to pass between the 
dorsal and ventral excretory vessels, and thence passes, as 
described, to the ovary. 
As the proglottides grow older, the uterus is seen to enlarge at 
