STUDIES ON THE ECTOPAEASITIC TREMATODES Oi* JAPAN. 159 



Vagina der Ces'toden in besserer Weise den neuen Verhaltnissen 

 angepasst haben wtirde," 



Dieckhoff, '^ who directed his attention specially to the canalis 

 genito-vntestinalis, is of the same opinion as Braun, under whose direc- 

 tion his studies were made. After describing, the canal in diiferent 

 species studied by him he says, "Ijima glaubte eine Nebeneinander- 

 stellung dessglben mit dem Laurer'schen Kanal der Digenea nicht von 

 der Hand weisen zu diirfen. Da aber auch bei Thiei'en mit unpararer, 

 dorsal miindender Vagina, wie z. B. bei Octobothrium lanceolatum und 

 Diplozoon paradozum, ein in den Darm fiihrender Kanal existirt, und 

 da auch uberhaupt die Ableitung d'es Laurer'schen Kanales aus den 

 paarigen Vaginen, wie mir scheint, geniigend dargethan ist, so ist 

 dieser Gedanke wohl nicht annehmbar"; and a little further on he 

 adds, " Vorlaufig muss man in dem Canalis vitello-intestinalis eine 

 Bildung sui generis sehen, deren genetische Beziehungen ganz 

 fraglich sind." 



Quite recently Looss^' has advanced a view which presents 

 considerable differences from those of the pi'eceding writers. He 

 considers the question from a purely morphological point of view and 

 comes to the conclusion that the uterus of the Trematodes is homo- 

 logous with the vag^ina of the Cestodes, the uterus of the latter with 



DO ' 



the Laurer's canal of the Digenea and with the canalis genito-intes- 

 tinalis of the Monogenea. The vagina of the latter he regards as a 

 structure sui generis. 



I have already in a preliminary paper '^ discussed briefly the 



1). Dieckhoff— Z. c. 



2). Looss — Ist der Laurer'sohe Kanal der Trematoden eine Vagina? Centralbl. f. 

 Batter, u. Parasitk., Bd. 13, 1893. p. 808 et infra. 



3). Der, Laurer'sohe Kanal und die Soheide. Centralbl. f. Bakter. u. Parasitenkunde, 

 Bd. 14, 1893. p. 797. 



