459 



vessel into the V. iliaca externa and at this point, lies ventral to 

 the Aa. iliacae. Its union with the V. iliaca externa corresponds 

 to vessel 1 of the Diagram. 



One instance was met with in which both of these veins {V.p.v.) 

 opened as single vessels into the Vv. iliacae externae. In Fig. 10 

 the union of the V. pudendo-vesicalis dextra with the Vv. iliacae 

 is seen to lie dorsal to the Aa. iliacae. When the arteries have 

 been removed, as in Fig. 11, it is seen that this vessel opens into 

 the angle of union of two veins which join the V. iliaca externa 

 and interna, respectively, and which correspond in their relative 

 position, to vessels 3 and 4 of the Diagram. The same conditions 

 are seen in Fig. 5. 



The V. pudendo-vesicalis was also found to open, on each side, 

 into a V. iliaca interna ventral to the A. iliaca interna. The portion 

 opening into the vein corresponds to the vessel marked 2 in the 

 Diagram (Fig. 19). See also Figs. 12 and 14. 



The following list indicates the different methods of union, found 

 by the writer, between the A. pudendo-vesicalis and the Vv. iliacae. 

 The numbers correspond to those in the Diagram (Fig. 19). 



Vessels that persist on: 

 Right side. Left side 



The above formulae show that although no instance was met 

 with in which the V. pudendo-vesicalis opened into the angle of 

 union of all four veins {1, 2, 3 and 4), that combinations of three 

 were not infrequent and that all four vessels were met with in the 

 preparations examined, 



HochstetterI) has described the A. pudendo-vesicalis ol 

 Echidna as consisting of a large vessel which arises from the 

 A. iliaca interna 2), Soon after its origin it divides into two branches, 



1) Semon's Forsch ungsreisen, Bd. 2, Lief. 3, p. 204. 



2) In several insta noes the A. pudendo-vesicalis was given off in 

 Didelphys from the A. iliaca externa. See Fig. 14 (sinistra). Also 

 Fig. 10 (sinistra). 



