STUDIES ON THE ECTOPARASITIC TREMATODES OF JAPAN. 219 



and towai'ds the left, and is continued into the ootyp, which is some- 

 what long in this species, and lies near the dorsal side of the body with 

 its length placed at right angles to the long axis of the body. The 

 uterus proceeds from the left end of the ootyp forwards and slightly 

 towards the right, and after reaching the median line of the body 

 some distance in front of the ovary, proceeds straight forwards to the 

 common genital opening. Vitcllarium extending from the level of the 

 vaginal opening to that of the posterior end of the testes. Paired yolk- 

 ducts asymmetrically disposed on the two sides. That of the right side 

 arises more in front than the other, a short distance in front of the 

 origin of the oviduct ; it at first proceeds perpendicularly to the long 

 axis of the body towards the median line, where it suddenly changes its 

 course and turns posteriorly and proceeding backwards with a few wind- 

 ings unites with its fellow of the other side just behind the ootyp. 

 The yolk-duct of the left side on the other hand arises from the vitel- 

 larium wholly behind the ovary, and proceeding straight towards 

 the median line of the bod}^, there bends at right angles to its previous 

 course and unites with its fellow coming from the front. The 

 unpaired yolk-duct is short, and proceeds from the point of union of the 

 paired yolk-ducts towards the right side, and opens into the oviduct 

 at about the middle of its whole length. Gcnito-intcstinal canal arising 

 from the oviduct side by side with, and just in front of, the unpaired 

 yolk-duct ; the canal at first very small, but soon swollen into a 

 voluminous receptaculum seminis, from the front end of which it 

 again continues, and proceeding towards the right Avith a few 

 convolutions, at last opens into the inner trunk of the intestine. 

 Vagina dorsal, a little behind the genital opening, armed with conical 

 teeth, and surrounded on both sides with a compact, refractive mass 

 of connective tissue, in consequence of which the opening is often seen 

 to have a swollen lip in specimens killed with hot sublimate ; vaginal 



