STUDIES ON THE ECTOPARASITIC TREMATODES OF JAPAN. 195 



ed at the mouth of the cylindrical sac before spoken of, the curved 

 portion projecting into the caviy of the atrium and the remaining 

 portion lying in the wall of the sac and the surrounding mesenchyma. 

 Ovary consisting of a A -shaped anterior portion and a posterior but 

 slightly slenderer portion which is turned spirally twice in the same 

 direction and once folded on itself in the opposite direction at the 

 hinder end. Vaginal opening a little less than twice as distant from 

 the front end of the ovary as it is behind the genital opening. The 

 vagiiml canal immediatly divides into two ; and the two canals thus 

 formed proceed a little way backwards, and turning to the ventral 

 side of the vas deferens unite on the dorsal side of the uterus, then 

 again separate from each other and become continuous with the paired 

 yolk-ducts. These begin in front of the anterior end of the ovary at 

 the distance of two-fifths the whole distance between the ovary and the 

 common genital opening, and unite with each other at the end of the 

 foremost third of the antero-posterior extension of the ovary. The 

 single duct thus formed opens into the oviduct about midway between 

 the beginning of the ootyp and the opening of the genito-intestinal canal. 

 The latt>er opens into the oviduct at the end of the anterior two-thirds 

 of the course of the oviduct. The vitellaria- of the two sides are entire- 

 ly distinct both in front and behind, extending into the caudal 

 portion and surrounding the two intestinal trunks. Testes occupying 

 about two- fifths the whole length of the body proper, posterior to the 

 ovary; large; about 27 in number. No branches on the median 

 side of the intestine^ the two trunks of which extend far into the caudal 

 disc and are in this region wholly destitute of lateral branches ; the 

 right trunk describing a larger curve in consequence of the general 

 asymmetry of the body. The caudal disc is bent at an angle to the 

 body proper and is only a little shorter than it. Posterior suckers about 

 75 on the right and 60 on the left side ; breadth 0.048-9.110 mm. 



