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veins and that is the frequency with which they occur. Although 

 during the present session about two hundred and sixty frogs of 

 (R. temporaria) have been examined while untergoing dissection in 

 the laboratory not one such anomaly has been noticed. The three 

 cases dealt with below were discovered last session as the result of 

 an examination of about four hundred frogs. In all thirteen or four- 

 teen instances have been recorded in Rana temporaria so that it 

 cannot be regarded as of very rare occurrence in this species. On 

 the other hand Dr. Ashworth informs me that, although a large 

 number of Rana esculenta pass through the laboratories at Edinburgh 

 every year, the retention of a posterior cardinal vein has not been 

 noticed and so far as I can ascertain no example of such an anomaly 

 has been recorded in this species of frog. The instances of the Uro- 

 dela, mentioned above, and the two in Limnodynastes peronii (1 and 

 7) however show that such abnormalities are not confined to Rana 

 temporaria. 



Description of Specimens. 



Specimen A c? Rana temporaria (Fig. 1). 



The following example, a full-grown male Rana temporaria Avas 

 brought to my notice by Dr. J. H. Ashworth of Edinburgh, whom 

 I have to thank for kindly sending me an accurate, coloured sketch 

 of the abnormality (made in 1898), and also for the details connected 

 therewith. The diagram given here (fig. 1) is based on the sketch. 



The condition in this frog is essentially similar to that described 

 previously (7 and 9) also in Rana temporaria. It differs from the 

 case described by Parker, where it was the left posterior cardinal 

 vein that persisted, and both from this and the one recorded by 

 myself in that the internal jugular and sub-scapular veins unite be- 

 fore joining the innominate portion of the posterior cardinal vein, 

 instead of opening separately into it. 



Only that part of the right posterior cardinal vein persists which 

 is situated in front of the kidney, and this opens directly into the 

 inter-renal vein without any connection with the lateral wall of the 

 kidney. The anterior end of the right posterior cardinal bends round 

 ventrally and mesially and, after receiving the short innominate vein 

 becomes slightly dilated. A similar enlargement has been noticed in 

 several of the cases previously described. Another point worthy of 

 note is the confluence of the vessels to form the right pre-caval vein. 

 Instead of the sub-clavian and external jugular veins opening into 



