have either two lateral openings (Polystonnatidae , and part of Microcotylidae) , 

 or they merge along the median line of the body and fornn a more or less 

 elongated unpaired duct opening on the ventral side (part of Microcotylidae, 

 Hexostomatidae). It is possible that Sphyranuridae are devoid of the vaginal 

 ducts although according to the old data (Braun, 1889-1893) it is known that 

 in Sphyranura osleri Wright there are two of them leading from the vitellaria 

 but not opening outside and terminating blindly. In the given species these 

 ducts play the role of the paired receptaculum seminis. Contemporary 

 research (Alvey, 1933a, 1933b) subject the data concerning such structure 

 in Sphyranura to doubts. Among the majority of Diclidophoridae the vaginal 



Fig. 103. Leptobothrium pristiuri 

 Gallien, adult worm. Natural size 

 1.6 mm (According to Gallien, 1937). 



Fig. 104. Anthocotyle merlucci 

 Beneden and Hesse, the diagram of 

 the structure of the female sex 

 system (According to Cerfontaine 

 1895, simplified). 



duct is absent; in rare cases it is paired, opening along the sides of the 

 body (Diclidophoropsis). Hexabothriidae and Diclybothriidae have a 

 divided vaginal duct which is closely connected to the vitellines and opens 

 by paired apertures on the ventral side or along the sides of the body. The 

 corresponding ducts of Chimaericolidae are most interestingly arranged. 

 They are paired, they begin from the vitelline ducts and open by two 

 apertures on the ventral side. At the same time and somewhat lower than 

 the external openings of each vaginal duct, there is a junction with a special 

 transversely-oriented vitelline gland. In such a fashion each duct has two 

 efferent openings, one internal and the other external. The physiological 

 significance of this is completely unknown, and such a structure is unheard 

 of in any other species of monogenetic trematodes. 



70 



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