322 ON SOMK TRKMATODE PARASIl ES OF AUSTRALIAN FROGS 



The main stem of the txcrttory systtrn of vessels extends 

 from the posterior extremity, where the pore opens, forwards 

 to the posterior side of the receptaculum seminis. The termi- 

 nal part is provided with a well-developed sphincter, and is 

 surrounded by a mass of glandular cells. From the anterior 

 end of the vesicle, two mam collecting tubes proceed forwards 

 as far as the intestinal fork. These lubes are of somewhat 

 varying calibre, but, on the whole, are nearly as wide as the 

 vesicle itself. In the first part of their course, they remain 

 closely applied to the sides of the receptaculum seminis, but 

 at its anterior border, they pass outwards till they reach the 

 outer aspect of the intestinal limbs, along which they run to 

 their anterior end. All along their course, they give off 

 smaller vessels (Figs. 60, 61, 62), the branches of which end 

 in flame-cells. The testes are large, and are situated in the 

 posterior half of the body, rather nearer the ventral sucker 

 than the posterior end. They lie, one on either side of the 

 middle line, one slightly or sometimes more markedly more 

 anterior than the other (Figs. 11, 57). The form is oval or a 

 little more elongated, with the outline, in most cases, but not 

 invariably, marked by a few deep indentations. The pos- 

 terior testis is invariably longer and narrower than the other ; 

 the average measurements are, anterior 0-529 x 0-379 mm., 

 posterior 0-668 x 0'346 nun. The vasa deferentia come off 

 from their anterior ends, and join to form the vesicula 

 seminalis, a little in front of the ventral sucker. The cirrus- 

 sac is tubular and very long, in the extended animal being 

 practically straight, while in preserved specimens it shows one 

 or two gentle curves. The vesicula seminalis within this, is 

 slightly coiled at each end (Figs. 59, 60). The prostate is 

 only poorly developed, but the cirrus is well developed, with 

 a strong ejaculatory duct (Fig. 58). The male duct opens 

 into a distinct genital chamber, and the genital opening is 

 situated on the ventral surface, about the middle line, just 

 beneath the pharynx (Fig. 58). 



The ovary is elongate, convex on its outer surface, concave 

 on the inner, and divided up into five or six deeply marked 



