ABXOKMALITIES IN THE COiMMON FROG. 493 



26. Abnormalities in the Common Frog (Bana iemporaria) . 

 By J. H. Lloyd, M.Sc, F.Z.S., Zoological Depart- 

 ment, University College, Cardiff". 



(Text-figure 1.) 



[Received .January 1.3, 1921 : Read April 5, 1921.] 



Both specimens described in the following notes were dis- 

 covered on dissecting a number of frogs for'class purposes at the 

 beginning of the present session. 



Specimen A. Persistence of the right Posterior Cardinal 

 vein in an adult male Rana temporaria. 



The occasional persistence of the posterior cardinal vein was 

 first noted by Howes (2) in 1888, in an adult female Rana 

 temper aina. In this specimen the postcaval vein was normalh'- 

 developed and the persistent left posterior cardinal functioned 

 as an azygos vein. The cardinal was continuous posteriorly with 

 the renal portal vein. According to Parker (6), Howes afterwards 

 came across another frog in which on almost similar arrangement 

 occui'red. 



In the following year Parker (6) described a male frog with 

 a persistent left posterior cardinal vein, in which the hepatic 

 veiiis opened direct into the sinus venosus. 



In 1905 Woodland (7) described a male. i?fm« temporaria in 

 which a large posterior cardinal vein persisted which was 

 continuous posteriorly with the enlarged right i-enal portal vein. 

 The venous blood was supplied to both kidneys by the left renal 

 portal only. 



O'Donoghue (4 & 5) has described eight cases of the persistence 

 of posterior cardinal veins in adiilt fi'ogs. Seven of his specimens 

 were males (six Rana temporaria and one Llmnodynastes ]}eronii), 

 and the other was a female Rana temporaria. The majority of 

 his specimens in addition exhibited abnormalities of the renal 

 portal veins. 



Description of Specimen A. 



This specimen exhibits a persistent right posterior cardinal 

 vein which runs from the anterior of the interrenal poi-tion of 

 the postcaval vein, and opens anteiioily into the subclavian vein 

 about halfway along its length. The interrenal vein is normally 

 developed and receives the renal and spermatic veins from the 

 kidneys and spermaries of right and left sides. There is abso- 

 lutely no trace of the left posterior cardinal vein or of the 

 postcaval vein anterior to the kidneys. The renal portal veins 

 exhibit no a,bnormalities. 



