F. J . Meggitt 
395 
run, slightly anteriorly, across the segment to the posterior border of 
the rostellum. 
Male Organs. The male organs first appear as an “Anlage” in the 
second segment and are not completely developed until the third 
(PI. XIX, fig. 2). The testes (t.) are 12-15 in number. They are 
irregular oval bodies, lying closely packed together at the posterior 
extremity of the proglottis: they have no definite arrangement. The 
vasa efferentia combine together at about the level of the shell-gland to 
form a dorsal vas deferens. This runs anteriorly to the border of the 
proglottis, bends and twists to form an elaborate coil, and then opens 
into the cirrus-sac. There is no vesicular seminalis, the coils of the vas 
deferens taking its place. The cirrus-sac lies transversely across the 
proglottis, reaching two-thirds of the way across. In it the vas deferens 
twists elaborately, ultimately ending in a long cirrus armed with fine 
spines. The opening of the cirrus is at the inner end of a long genital 
sinus, making an angle of 45° with the side of the proglottis, and opening 
to the exterior almost at the anterior corner of the segment. The 
position of the genital pore thus formed alternates regularly from side 
to side. The cirrus-sac generally persists in the last proglottis, but the 
testes disappear as soon as the eggs begin to be distributed in the 
parenchyma. In certain cases self-fertilization occurs. In three stained 
specimens the cirrus is inserted into the vagina (PL XIX, fig. 3), this 
being also seen in living forms, and many times it is thrust into the 
genital sinus without being turned to the exterior. On the other hand, 
it is often protruding out of the genital sinus, indicating cross-fertiliza¬ 
tion, and this method seems to be more usual than the other. 
Female Organs. The female organs (PI. XIX, fig. 2) conform to the 
usual Davainea type. They are first developed in the third segment, 
in which the “Anlagen” of vagina and receptaculum seminis can be 
seen. In the following segment they are completely developed and are 
functional. The uterus is not developed until the fifth proglottis and 
only lasts until the sixth. In that proglottis, the receptaculum seminis 
and vagina alone of the female organs remain, and the eggs begin to 
pass into the parenchyma. The mature eggs are to be found in the 
seventh segment, although they may sometimes be present in the 
sixth. In the centre of the proglottis and with its long axis directed 
antero-posteriorly is a large oval receptaculum seminis (r.s.) filled with 
spermatozoa, and communicating with the exterior by means of a 
much-coiled vagina (v.): this latter opens into the genital sinus just 
posterior to the cirrus. At the posterior extremity of the receptaculum 
Parasitology yin 26 
