457 



thus far described for Didelphys are, in all probability the result 

 of modifications of an embryonic "Ground Type" arrangement of the 

 veins which unite to form the V. cava posterior, similar to that 

 described by Hochstetter for Echidna. 



The V. pudendo-vesioalis ^). 



The term pudendo-vesicalis is used to designate that vein which 

 originates in the regions supplied by the A. pudendo-vesicalis, a name 

 used by Hochstetter for a corresponding artery in Echidna^). 



i.e.S. 



Fig. 19. Diagram to illustrate the mode of union of V. pudendo-vesicalis with 

 Vv. iliacae. For abbreviations see under Figs. 1 and 2. For numbers 1, 2, 3 and 4i 

 see following text. Type I. Ventral aspect. 



1) In my description of the V. pudendo-vesicalis I fear I have not 

 made clear that the subdivision of this vein called by me the V. pu- 

 denda is, on account of the source of its tributaries, more likel}^ to be 

 an accessory pudic vein than a V. vesicalis inferior. It may also be 

 said of the corresponding artery, that it is, in all probability, an acces- 

 sory pudic artery and not an A. vesicalis inferior. In using the term 

 pudendo-vesicalis I do not mean to imply that there is not an A. and 

 V. pudenda interna in addition to the accessory pudic vessels, but only 

 to emphasize the circumstance that the conditions which exist in 

 Didelphys are essentially the same as those in Echidna, so far as 

 the presence of a Truncus pudendo-vesicalis is concerned, 



2) Semon's Forschungsreisen, Bd, 2, Lief. 3, p. 204. 



