862 DR. F. E. BEDDARD ON 
met with. The anterior relatively broader segments are rather 
flattened in transverse section. The posterior proglottids are 
sometimes quite cylindrical in form, being circular in section. Or 
they may be more oval, though still of great depth dorso- 
ventrally. 
In transverse sections such as are represented in text-fig. 6, 
the cortical layer is seen to be fully as thick as, and occasionally 
even a shade thicker than, the medulla. The distribution of the 
longitudinal muscular layer seems to be very much as it has been 
described by Fuhrmann* for the allied species i. numida. Next 
to the transverse muscles there is a layer of rather widely spaced 
bundles with not more and sometimes less than 5 or 6 fibres in 
each. Between these and the subcuticular layer are numerous 
scattered longitudinal fibres implanted singly. The transverse 
fibres form a rather thick layer, and in the anterior region of the 
proglottid, where the medulla is free from the testes ete., and in 
the area partially occupied by the paruterine organ, the trans- 
verse fibres encroach further upon the medullary parenchyma, 
which is largely pervaded by them. Dorso-ventral fibres are also 
abundant in the medullary layer and, as mentioned later, are not 
at first displaced by the paruterine organ. 
The water-vascular system consists of the two usual longi- 
tudinal vessels, of which the very much larger ventral vessels are 
united by an equally wide transverse vessel at the posterior end 
of each proglottid. The opening of the longitudinal vessel into 
the transverse vessel is guarded by a valve which prevents the 
reflux of fluid into the longitudinal vessel anteriorly. I could find 
no other branches of the ventral vessel to form a network such as 
appears to exist according to Ransom in habdometra nullicollis. 
The dorsal vessel lies above the ventral and often rather to the 
inside ; it is very small but has relatively thick walls. The 
genital ducts pass between the two vessels and below the nerve- 
eord, which is displaced towards the dorsal side from its usual 
position, where the ducts pass beneath it. It will be noted that 
in the relations of the nerve-cord to the genital ducts the present 
species differs from both kh. nudlicollis and Kh. similis, where 
the genital ducts pass dorsal of the nerve-cord. 
The testes are numerous, and often very closely pressed to- 
gether. ‘They lie on all sides of the ovary and vitelline gland, 
being found laterally and posteriorly as well as anteriorly in the 
segment. In the most mature segments the testes are only plainly 
to be recognised posteriorly in the segment lying behind the 
uterus. Laterally the testes in the ripe but not fully mature 
_proglottids extend as far as the water-vessels on each side. An- 
teriorly the boundary of the area occupied by the testes is some 
way short of the anterior margin of the proglottid. In transverse 
sections of proglottids where the uterus is nearly fully developed, 
the testes are seen to lie dorsally of the uterus, which latter organ 
* Res. Swed. Zool. Exp. Egypt, pt. iii. No. 27, 1909. 
