388 
A Tri-Radiate Tapeworm 
The courses taken by the female ducts are irregular in the extreme. 
A typical course and arrangement can be distinguished, but- this is 
liable to almost any variation. The oviduct (ovd.) joining the ovary 
and receptaculum seminis runs straight from the inner end of the latter 
towards the former: after crossing the vitelline bridge it bends towards 
arm 2, then runs for a short distance anteriorly or posteriorly and bends 
back again to open into the ovary through a small but pronounced 
ooclapt (ode.). The part of the oviduct (ovd.') leading to the shell-gland 
separates from that leading to the ovary at any point before the vitelline 
bridge. It normally bends towards arm 2 and, after several variable 
curves, opens into the ootype where it receives the vitelline duct (y.d.). 
In one dubious case, the vitelline duct apparently opened into the oviduct 
after it had left the ootype. After leaving the ootype, the oviduct runs 
towards the middle point of the junction of arms 1 and 2 for a short 
distance, and then curves round to run in the opposite direction close 
to the ovarian side of the receptaculum seminis. It finally turns in the 
direction of the ovary and opens into the uterus (ut.). This is a rather 
narrow, little-branched tube extending nearly to the dorsal excretory 
vessels of arms 2 and 3, following the outline of the ovary. 
In its opening to the central space, the receptaculum seminis is 
exceedingly peculiar and variable. The simplest case is where it opens 
into a vagina, which, after a short bend in any direction, opens into the 
central space. A more usual arrangement is for several receptaculae 
seminae to communicate with each other first. Of the series, the most 
anterior opens into a short narrow duct leading directly posteriorly and 
opening into what would normally be the external end of the succeeding 
receptaculum seminis. This again communicates by means of a similar 
duct with the next receptaculum seminalis, and so on until the end of- 
the series is reached, the last receptaculum seminalis communicating 
only with its predecessor and its own female organs. In one special 
case, a receptaculum seminis was absent, the connecting duct opening 
directly into the ovary. About half-way along the series of short ducts 
connecting the whole series of receptaculae seminae (usually three or 
four) is another similar duct, opening at one end into the connecting 
ducts and at the other into the central space, fairly close to the opening 
of the cirrus. 
