122 



Nachdruck verboten. 



A further Xote on a Yariation in Rana temporaria. 



By Ebnest Warren D. Sc. Assistant Lecturer in Zoology University 



College London. 



With one Figure. 



In 1898 (Anat. Anz. XIV p. 551) I communicated a note on an 

 abnormality in a frog consisting of a blood-vessel passing from the 

 apex of the left lung to the hepatic portal blood system. 



Since then two other examples of a similar abnormality have been 

 found in the class-dissections. Last year a nearly identical case 

 occurred where the vessel passed from the right lung instead of the 

 left and almost certainly joined on to the hepatic portal, but un- 

 fortunately the student 

 had dissected too far to 

 be absolutely certain. 



This year I have ob- 

 served a more interesting 

 case. The accompanying 

 figure will explain it; an 

 artery and a vein ran 

 side by side, the former 

 was continuous with the 

 posterior mesenteric ar- 

 tery, the latter forked, 

 one branch being conti- 

 nuous with the renal por- 

 tal and the other with 

 the rectal vein of the 

 hepatic portal. 



This arrangement of 



blood-vessels is strikingly 



similar to that seen in a 



Teleostean fish where an 



artery runs from the mesenteric artery into the rete mirabile of the 



air-bladder and from there the blood is carried by a vein into the 



portal system. 



HEPATIC POflTAL 



-RENAL PORTAL 



