ART. 13 TREMATODE PARASITES OF MARINE MAMMALS PRICE 51 



to form a seminal receptacle measurinc: 170/i, long by 57)u, wide. 

 Vitellaria weakly developed, consisting of a few follicles situated 

 alonsr the vitelline duct at each side of the intercecal field. Uterus 

 slender and occupying the intercecal space in the equatorial third of 

 the body ; during its course the uterus describes a number of loops 

 which form a treelike pattern. The distal portion of the uterus is 

 expanded to form an egg reservoir and continues as a slender vagina, 

 which opens beside the male genital aperture. Eggs oval in outline, 

 29^ long by d/x wide, provided with a long, slender filament at each 

 pole. 

 Host. — Halicore dugong. 

 Location. — Eustachian tubes and esophagus. 

 Distrihutlon. — Philippine Islands ; Australia. 



Remarks. — This species was named Monostomum dujonis by 

 Leuckart (1874) in a review of Zeiler's (1874) paper " Uber Leu- 

 cochJoridmm paradoxum Cams and die weitere Entwickelung seiner 

 Distomenbrut." In this review, Leuckart, in commenting on the 

 genital system of L. paradoocum., stated : " Und seine Generations- 

 organe in alien ihren Theilen vollstandig und deutlich erkennen 

 liisst. Die Ausmiindung derselben liegt, wie sonst nur bei wenigen 

 Distomeen — Ref. kennt audi ein Monostomum, das sich ganz ahnlich 

 verhalt, M. dujonis., das Semper in den Eustachischen Rohren des 

 Dujung der Philippinen sammelte und dem Ref. freundlichst zur 

 Untersuchung uberlassen hat — an Hinterende des Korpers, dicht 

 neben der des excretorischen Apparates." Fischer's (1883) descrip- 

 tion of Opisthotrema cochleare is based unquestionably upon a study 

 of the specimens which Leuckart referred to, since he stated in the 

 introduction of his paper : " Besagte Form wurcle von Herrn Prof. 

 Semper in Wiirtzburg auf seiner Expedition nach den Phili})pinen 

 gesammelt. Sie entstammt der Paukenhohle von Halicore Dugong." 

 The name given to this worm by Leuckart can not be regarded as 

 a nomen nudum because an important morphological character, the 

 jDosition of the genital pore, is pointed out and in addition are given 

 the host and habitat of the species. It is, therefore, the opinion of the 

 writer that the correct name for this species is OpisthotTema dujonis 

 (Leuckart), since the rules of zoological nomenclature state: "Art. 

 25. — The valid name of a genus or species can be only that name 

 under which it was first designated on the condition: a) That this 

 name was published and accompanied by an indication, or a defi- 

 nition, or a description;" etc. The description given by Leuckart 

 is more in the form of a comparison than an actual description, but 

 it appears sufficient to fix the specific name, since the rules do not 

 state how much description should be given. 



