STUDIES 0^' THE ECTOPARASITIC TBEMATODES OF JAPAN. 225 



backwards between the suckers, and the other enters the caudal 

 appendage and ends a little before reaching the level of the small 

 suckers at the extx'emity. Genital opening on the same level with the 

 posterior end of the oesophagus, without any chitinous armature. 

 Omnj long, with numerous windings (PI. XY, fig. 1), situated near 

 the hinder end of the anterior half of the body ; of small size in 

 relation to the whole body. The ovidtict proceeds from its origin for 

 a certain distance forwards with a few windings, and then sharply 

 turns backwards and towards the right, and after proceeding posteriorly 

 for a short distance, again turns sharply forwards and is continued 

 into the ootijp. This is tolerably long and lies with its long 

 axis nearly coinciding with that of the body. From its front end 

 the ■uterus proceedi3 straight forwards toward the genital opening. 

 Vitellarium extending from a little behind the anterior end of the in- 

 testinal trunks to the point of their union at the level of the first 

 pair of posterior suckers ; separate in front but continuous behind. 

 Pairei yolk-ducts perfectly symmetrical on the two sides, arising from 

 the vitellarium at about the level of the front end of the last 

 third of the anterior half of the whole body ; proceeding at first 

 somewhat forwards and towards the median line, then bend- 

 injr backwards, and unitinsr with each other in it to form a sort of 

 vitelline reservoir. From this a small unpaired ^jollc-diict proceeds 

 backwards and opens into the oviduct at the point where this 

 turns sharply backwards towards the ootyp. The genito-intestinal 

 cuial, arising from the oviduct side by side with the unpaired yolk- 

 duct, proceeds at first towards the right, then turns backwards 

 and finally opens into the intestine. B,eceptaculum seminis situated on 

 the right side of the median line just in front of the ovary, large, 

 oval, with a long neck which opens into the oviduct side by side 

 with the genito-intestinal canal. Testes numerous, of moderate size ; 



