458 



N/i.e-d 



Fig. 20 



The manner in which this vein is connected with the Vv. iliacae 

 is extremely variable in Didelphys. In order to best understand 

 these variations the following Diagram is appended. 



In the Diagram (Fig. 19) the V. pudendo-vesicalis (V.p.v.) is 

 seen to open, on each side, into the angle of union of four veins. 

 Two of these veins open 

 into the Vv. iliacae internae, 

 while the remaining two 

 open into the Vv. iliacae 

 externae. The anterior pair 

 of these veins, numbered 

 1 and 2, lie ventral, and the 

 posterior pair , numbered 

 3 and 4, lie dorsal to the 

 Aa. iliacae. The writer does 

 not wish to insinuate that 

 this Diagram represents the 

 actual condition met with 

 in the embryo. That can 

 only be determined by fol- 

 lowing the development of 

 this vessel in the embryo. 

 A description of these ves- 

 sels as found in the adult 

 will now be given. 



In the ventral view, 

 Fig. 20, the V. pudendo- 

 vesicalis, of each side, opens 

 into the angle of union of 

 two veins, 1 and 2, which 

 lie ventral to the arteries 

 and open into the Vv. iliacae 

 externae and internae, 

 respectively. In the dorsal 

 view, Fig. 21, it is also 



seen that the V. pudendo-vesicalis sinistra opens into an additional 

 vein (-7) that lies dorsal to the Aa. iliacae and joins the V. iliaca 

 externa. The connection 3 is absent on the right side. 



In Fig. 6 the V. pudendo-vesicalis dextra opens into the angle 

 of union of two veins which correspond to vessels 1 and 2 of the 

 Diagram ; while the V. pudendo-vesicalis sinistra opens as a single 



Vi£.s..^ 



V.i.e.cC. 



I.e. 



Fig. 20. Ventral aspect. Adult 2, Type III, A. 



Fig. 21. Dor.sal aspect of Fig. 20. 



For abbreviations see under Figs. 1 and 2. 



