1888.] VEINS IN THE ANUROUS AMPHIBIA. 123 



between a late-formed hepatic vessel and one or both of the posterior 

 cardinal veins. To that portion which is derived from the cardinal 

 veins, and which receives the venae renales revehentes, he applies 

 the term " urniere Abschnitte'" ; it is represented, in the adults of tlie 

 higher forms, by all behind and including the renal veins. He further 

 asserts that whereas in Amphibia the two posterior cardinals become 

 confluent to form this, in Mammalia', on the other hand, the 

 cardinal vein of the right side also gives origin to it. 



On the completion of the above-named developmental processes 

 the anterior or prerenal portions of the posterior cardinal veins either 

 become modified, to form the azygos and hemi-azygos veins of human 

 anatomy, or, for the most part, disappear. Hochstetter has worked 

 out the steps in the development in Bombinator, Pelohates, Rana, 

 and Salamandra among Amphibia. So far as Bombinator is concerned, 

 he fully confirms the classical researches of Goette, except for the 

 fact tliat that author failed to observe the persistence of the entire 

 posterior cardinals in the adult. Hochstetter has shown that in 

 Bombinator igneus their anterior portions (morpiiological azygos 

 veins) not only persist for life, but that with their confluence pos- 

 teriorly, to form the hinder part of the vena cava inferior, their 

 original continuity is not destroyed. There thus result two well- 

 defined veins {c.p. of fig.), which pass upwards and forwards, side 

 by side with the arches of the aorta, putting, as in some Urodeles, 

 the fully formed vena cava inferior into direct communication with 

 the veins of the anterior extremities. 



In Rana, according to Hochstetter, the anterior segments of the pos- 

 terior cardinals atrophy during metamorphosis. An individual example 

 of the Common Frog (R. temporaria, adult $ ) has, however, recently 

 come into my hands ^ in which the vessel persisted for its entirety on 

 one side (see fig., p. 124)^. Not only so, but its development had con- 

 tinued pari passu with that of other related parts — in e.xcess of that 

 seen even in Bombinator. The drawing speaks for itself as to detail, 

 and it mustsuflfice to point out that, except as concerned the presence 

 and relations of this vein, no noteworthy difference could be detected 

 between the distribution of even the smaller vessels in this animal 

 and those of the ordinary adult. The least normal among the veins 

 were the ovarian ones (ov.), which, as will be seen, were strikingly 

 asymmetrical. There was not the remotest trace of the correspond- 

 ing portion of the right posterior cardinal. 



The persistence of this vein in one of the Kanidse is, in itself, 

 deserving of record ; but careful comparison with Bombinator has 

 revealed an interesting difference between the two. Hochstetter con- 

 firms and extends Goette's discovery that the main trunks of the venae 

 renales advehentes are primarily continuous with the posterior car- 

 dinals, forming trunks (Jacobson's veins) the lower ends of which, 

 subsequently receiving the iliac veins, become the renal portals 



1 Anat. Anz. vol. ii. 1887, p. 519. 



" Thanks to tbe diligence of my pupil, Mr. W. F. Hume. 

 ' As these sheets were passing through the press I met with the same con- 

 dition in a male of Bombinator bombinus. 



