STUDIES OX THE ECTOrAliASlTiC TllEMATODES OF JAl'AX. 2lo 



ceeds straight forwards toAvard.s the coniinon genital opening, raired 

 yolk-ducts slightly asymmetrical, making an angle with the Ion/»- 

 axis of the body, and uniting with each otlier on the same 

 level as the fore end of the ovary. The unpaired yolk-duct 

 thence proceeds backwards and towards the left, and unites with 

 the oviduct in the median line of the b(xly, just wliere the oviduct 

 bends to the left towards the ootyp. Gcuito-intcstlnal cuial tolerably 

 long, and arising from tlie oviduct side by side with the veccplaculuni 

 sùminii^^ jiroceeds slightly forwards and towards the right, and finally 

 opens into the intestine. Testes exceedingly numerous, tolerably 

 large, extending from a little behind the common genital opening to 

 the level of the first pair of posterior suckers, and occupying the 

 whole region enclosed by the two intestinal trunks, /. c, three- 

 fifths of the total breadth of the body. ) 'as deferens as usual on the 

 dors:d side of the uterus. 



Hahilat — Mouth-cavity <jf Choerops Japonicus (Jap. Kol)u-dai or 

 Kan-dai). Young specimens also on the gill. 



Locality — Mitsugahama (Prov. lyo). 



Drtic— August 1889. 



4. Diclidopliom ietrodonis, n. sp. 

 (PI. X, figs. 1-4.) 

 Body long and slender, s[)athulate, 5-15 mm. long^ divisiljle into 

 three portions, an anterior, fusiform portion a little over half the entire 

 length of the body, a middle, slender, stalk-like portion half as long- 

 as the former, and the caudal disc a little less than half the stalk-like 

 portion and bearing the suckers alc^ng its margin on the ventral side ; 

 the three portions, however, gradually passing into each other with- 

 out any sharp demiu'cation. Suckers sessile, elliptical, ai-rnnged in a 

 dee[) horse-shoe shape, the open end of which is directed forwards ; 



