Frederic T. Lewis 



237 



cardinal vein, and dorsal to the Urnierenvene. My examination of 

 these renal relations confirms the observations of Hochstetter (88 and 

 93) in almost every particular. 



Figs. 7 and 8, PI. II, from a rabbit of 14.5 mm., show at Y the new 

 cross connection between the cardinal veins in their pelvic portion. 

 The kidney lies behind the AVolffian body, the hihis of which it com- 

 presses, as shown in Fig. 9. The renal vein is a branch of the cardinal 

 at the level of the large anastomosis of that vessel with the subcardiual. 

 In the pelvic part of its course the cardinal receives the vena iumbalis 



Fig. 9. Rabbit embryo of 14.5 mm., 14 days, 18 hours ( ? ). Series 143, section 827. 



transversa posterior. This is a large irregular vessel in the body wall, 

 connected with one or two intersegmental veins, and suggesting the 

 trunk which was split off by the kidney shown in Fig. 4, PI, I. The 

 intersegmental veins were easily followed in younger and 'in older em- 

 bryos, but at this stage their connections with the cardinal are very 

 obscure. This may be due to distortion caused by the migration of 

 the renal artery. The superior section of the cardinal receives a large 

 • transverse lumbar vein, two intersegmental veins, and small vessels 

 from mesenchyma in the suprarenal region. On the right side a con- 

 siderable area fuses with the subcardinal and is incorporated in the 

 vena cava. The mesonephric arteries become obliterated. In a rabbit 



