TRIRADIATE TAPEWORMS FROM HOUNDS AND JACKAL.               398

looks like a rounded cone and is about 25 μ in length and 13 μ in width ; when it is
viewed on face, it is quadrangular in form and has a small notch in the middle of
the free border, attempting to divide it into two halves and the plane of each half
inclines towards the other, making a very obtuse angle in relation to the notch.
This gives the guard an appearance of being bifid when looked at from certain
angles.

The scolex has six suckers on it, each having a bulb diameter of about 0.15 mm.
and these suckers are arranged around the widest portion of the head. In the
parenchyma of the head, about the level of the suckers or a little behind them, the
three excretory channels originate from a common fairly circular canal, situated at
right angles to the long axis of the head. Each channel passes down each angle of
the trilobed strobila. The length of the strobila is about 25 cm. and may vary.
The musculature is well formed in each segment. The genital primordia appear in
about the 20th segment from the head. Each mature segment measures 1.65 mm.
wide and 1.4 mm. long. The gravid segments, on the other hand, are longer than
broad and are about half as long again as the mature segments.

                                           MALE GENITALIA.

There are about 100 to 150 irregularly spherical testes, confined to the field,
between the excretory channel and the stem of the uterus in each ply or lobe of a
segment. The vas deferens is a wide, very convoluted tube and originates from
near the anterior border of the ovary and the lateral margin of the stem of the
uterus. It runs towards the lateral margin and meets a well formed cirrus sac and
cirrus before it opens in the genital pore. The cirrus sac is oval, longer than broad,
and length being 0.3 mm. The genital opening is near the middle of the lateral
margin and these openings alternate irregularly on any one of the plies or lobes of
the segment.

                                           FEMALE GENITALIA.

The ovary is placed in the posterior field of each segment. It is trilobed, each
lobe is fan shaped and is placed in each ply or lobe of a segment. From the meeting
point of the lobes, the uterus begins as a median stem, running in the middle of the
segment. It has a fairly dilated free end. Later on, as it becomes gravid, it sends fine
branches into the plies or lobes of the segment. The vagina is a fairly thick-walled
tube and originates from the inter-ovarian field. It runs forward for a short dis-
tance, then bends towards the margin and runs parallel and posterior to the vas
deferens before it opens in the genital pore. The vitellaria are situated posterior
to the ovary and appear to be trilobed like the ovary. The ova are spherical or

                                                                                                             H 2