( «9 ) 





-is--- 'f-^ 



/■ 



Fig, 2. Course of Wolffian and Müllerian ducts in a marsupial young 



one of Phalangista vulpina. j 

 w. g. Wolffian duct. m. g. Müllerian duct. s. ti. g. Siiius uro-genitalis. 



duct i. e. at a stage, which occurs as a femjioraiy condition in the 

 monodelphic mammals, at any rate in so far as these have been 

 examined, while in the latter they move, before the terminal piece 

 of the Wolffian duct has been ijieorporated in the wall of the 

 bladder, towards the dorso-lateral wall of that passage, so that in 

 the adult condition they are found laterally of the Wolffian and 

 the Müllerian duct. Although I have not been able to test this 

 theoretical consideration by observations of my own, yet it seems to 

 me that besides the cause, postulated b}' Keibel for the course of 

 the ureters medially of the Müllerian duct, the spiral course of tiie 

 Wolffian duct and the consequent torsion of this canal, must 

 certainly have an influence and probably a not inconsiderable one 

 on the origin of this course. 



A notable fact in this respect is that in male marsupials a masculine 

 uterus is absent, that no remnants have been found of the caudal 

 terminals of the Mülleiian ducts, as is expressly stated by Weber ^) 

 and Disselhorst*). Only Hypsiprymnus would be an exception to this, 

 according to Owen. 



At the stage, observed by me, (he terminals of the Müllerian 



1) M. Weber. Die Saugetiere. Jena. G. Fischer 1904. 



2) R. Disselhorst. Ausführapparat und Anhangsdrüsen der mannlicben Geschlechts- 

 organen in : Letirbuch der vergleichend mikroskopischen Anatomie der Wirbeltiere, 

 herausgegeben von A. Oppel. 4er Teil. 



