STUDIES ON THE ECTOPARASITIC TREMATODES OF JAPAX. 941 



region between the intestinal trunks, mof^tly l^ehind the ovary, 

 but extending" also forwards on l)oth sides about niidwav up the 

 ovary. Numerous vasa eft'ercntin uniting in the median line and 

 forming a single ms deferens^ wliich, Avith numerous convolutions, 

 proceeds forwards, keeping itself close on the left side of the 

 ovary, and reaching the front end of the latter here f^rms a long 

 loop with its closed end directed forwards and towards the right ; 

 after this the vas deferens proceeds, still with complicated con- 

 volutions, for a short distance forwards, then bends towards the right; 

 and entering the penis at its Inse, finally opens into its cavitv on 

 the top of a papilla, at a short distance from its apex ; its caliljre 

 generally decreasing all -along after the large loop at the front end 

 of the ovary. 



This species has a light flesh-red colour of its own, which does 

 not wholly disappear in 'alcoholic specimens. 



lldhitat — Inner side of the gill-plates of Hislioplionis sp. ('bip. 

 Ktijiki). 



Localitij — Misaki. 



Da ^6'— August 1891. 



2. Tristomum ovah', n. sp. 

 (PI. XXIII; n. XXIY, figs. 1-5.) 

 IJûdi/ oval, about lo mm. hjng by 12 mm. liroad or larger, 

 sometimes approacliing more nearly a circle, witli numerous, uniform- 

 ly scattered conspicuous papillae on the ventral surf ice, dorsally smooth. 

 Anterior border convex, separated from the lateral borders by a deep, 

 large notch on each side, at the apex (^f which is attached the anterior 

 sucker of either side; posterior end with a large obtuse notch. Lateral 

 margins entire, destitute of chitinous bodies. Anterior suclcrs of moderate 

 size, nearly circular, with numerous papillae on their inner margins. 



