445 



by the union of a V. iliaca externa and interna, ventral to the 

 Truncus hypogastrico-sacralis ^). 



The preparation represented by Fig. 1, in some respects, corre- 

 sponds to the conditions met with in Hal mat urns. It is inter- 

 esting to note, however, that 

 in Halmaturus aV. iliaca 

 communis and a Truncus 

 hypogastrico-sacralis are the 

 rule, while in Fig. 1 the 

 reverse conditions are met 

 with, namely, an A. iliaca 

 communis and a V. iliaca 

 interna communis. 



In Fig, 3 the V. cava \y- , 

 posterior is formed in sub- 

 stantially the same manner 

 as in Fig. 1. In Fig. 3, 

 however, the V. cava is bi- 

 furcated caudad of the V. 

 spermatica interna sinistra 

 ( V.s.i.s.). In consequence 

 of this bifurcation the V. iliaca interna communis unites with the 

 right and the left V. cava, respectively, the union on the right side 

 being the more important of the two. 



Type U. Those cases in which the Vv, iliacae in- 

 ternae unite with the Vv, iliacae externae to 

 form the V, cava posterior, dorsal to the A a. 

 iliacae communes or dorsal to the Aorta, 



Six examples of this Type were met with distributed among four 

 males and two females. 



In Fig, 4, which is a ventral view, the V, cava posterior is, as 

 in Fig, 3, bifurcated caudad of the V. spermatica interna sinistra 

 {V.s.i.s.). The Vv, iliacae internae, after uniting with each other in 

 the median line, ventral to the A, sacralis media, unite with 

 the Vv. iliacae externae to form the Vv, cavae , by means of t w o 

 vessels that lie dorsal to the A a. iliacae communes. 



An interesting variation of the conditions represented in Fig, 4, 

 is shown in Fig, 5 (dorsal view). Here the Vv, iliacae internae, 



Fig, 3. Ventral aspect. Adult J» Type I. 

 For abbreviations see under Figs. 1 and 2. 



1) See Hochstetter's Fig, 13, Morph. Jahrb., Bd. 20, p. 626. 



