632 MR. c. H. o'donoghue on the 



Tlie Right Efferent Renal Vein (Y. venalis rovehens, Sclilemm) 

 originates along the inner margin of the kidney at its posterior 

 end, runs to the anterior end, and after a short independent 

 course in fi-ont of the kidney unites with its fellow of the opposite 

 side to give rise to the postcaval vein. 



The Left Efferent Renal Yehi also has its origin along the inner 

 margin of the kidney. But, unlike the right, it receives branches 

 from tlie supra-renal body, the ovary, and the left oviduct in its 

 course from the kidney to the point where it unites with its 

 fellow. Thus : — 



i. The Left Ovarian Veins are numerous small tributaries 



flowing into the left eflerent renal veins. 

 ii. The Left Supra-Renal Veins ai^e a large number of small 

 branches running from the supra-renal body into the 

 efferent renal vein, to which it is closely attached. They 

 return the blood brought to that body by the supra-renal 

 portal veins. 

 iii. The Left Oviducal Vein is a large vein leaving the oviduct 

 at the level of the fimbriated funnel and flowing into the 

 efterent renal vein just in front of the supra-renal body. 

 It returns blood fi'om the oviducal sinus. 

 A. The Left Oviducal Shins is a wide thin-walled vessel 

 which runs from the extreme anterior end of the ovi- 

 ducal funnel backwards to about the level of the middle 

 of the corresponding kidney. It is very conspicuous in 

 injected specimens and was present in all the female 

 examples of 7\ natrlx that I have examined, although it 

 does not appear to have been recorded in any other 

 Ophidian. 



The Post-Caval Vein (V. cava posterior, Schlemm) is formed, 

 as has been stated above, by the union of the two etterent renal 

 veins. It passes forward, dorsal to the gut, freely in the mesen- 

 tery to the posterior extremity of the liver, and then along in a 

 groove in the ventral surface of that organ to its anterior end. 

 After leaving the liver it runs almost straight forward, ventral to 

 the right systemic ai-ch and unites with the right pi'e-caval to 

 form the larger division of the sinus venosus. Soon after its 

 origin it receives veins from the right ovaiy, the supra-renal 

 body, and the oviduct. Thus : — 



i. The Right Ovarian Veins are similar to those of the opposite 



side, 

 ii. The Right Supra-Renal Veins also resemble those on the 

 left and return the blood gathered by the supra-renal 

 portal veins. 

 iii. The Right Oirlducal Vein is like its fellow on the left and 

 comes from an oviducal sinus. 

 A. The 2iight Oviducal Sinus extends along the oviduct from 

 the .antei'ior end of the fmmel to about the level of the 

 middle of the right kidney. 



