STUDIES OX THE ECTOPAltASmc TllEMATODES OF JAPAX. 253 



this is behind the iinterior sucker, but a little neai'er the median line; 

 vaginal canal swollen at the beginning, then becoming very fine, and 

 taking the usual course and describing some convolutions, opens at 

 last into the yolk-reservoir after it has formed an elongated, oval, 

 capacious reccptaculum scminis just in front of the reservoir. Testes nu- 

 merous, irregularly polygonal, confined to the median region between 

 the intestinal trunks, mostly behind the ovary. 



Habitat — Carapace of a copepod, probably of the genus Parapetalus, 

 parasitic on the gill of Thijniius albacora (Jap. Ssda-gatsuwo). 



Locality — Misaki. 



Dflic— August 1891. 



Tokyo, March 12, 1894. 



