136 



clearly that the post-caval vein of the adult is composed of three 

 distinct parts. An inter-renal portion is derived from the fused median 

 portions of the loops formed by the posterior cardinal veins around 

 the growing mesonephroi; an anterior portion is formed from the 

 hepatic veins; an intermediate part arises as a vascular connection 

 between the right posterior cardinal vein and the liver. In the follow- 

 ing cases this last, intermediate, portion of the post-caval vein has, 

 for some reason at present unknown, failed to develojie. 



In an interesting note Kerr (5) has indicated how the renal- 

 hepatic connection may have originated in the course of phylogeny. 

 He points out that in the lung-fishes, " the kidneys extend relatively 

 far forward, while the liver extends relatively far back along the 

 right side of the splanchnocoele " and as a result we find " in Lepi- 

 dosiren and Protopterus, that the tip of the liver is in contact, and 

 fused, with the tip of the right kidney. " In Polypterus also there is 

 a similar connection, "a true primitive posterior vena cava." 



Since a previous communication (7) in which all the similar 

 abnormalities in the fi'og then known to me, were noted, my atten- 

 tion has been sailed to a note by Lyle (6) in which an abnormal 

 arrangement of the renal-portal vein is recorded thus: — "The renal 

 portal veins were also formed in the usual manner, and the left one 

 entered the outer side of the left kidney, but the right one divided 

 into three branches, one to the outer side of the right kidney, a se- 

 cond branch crossed the kidney dorsally, and the third branch crossed 

 the kidney ventrally; both these latter opened straight into the posterior 

 vena cava. ''^) This animal was probably Eana temporaria but there 

 is no record of whether it was male or female. 



An absence of the intermediate part of the post-caval vein and con- 

 sequent retention of one of the posterior cardinal veins has been recor- 

 ded in Salamandra maculosa and in Amblystomum tigrinum (Siredon), 

 so that this abnormality is not confined to the Anura. According to 

 Joseph (4), Hoghstetter recorded the persistence of a right posterior 

 cardinal vein in Salamandra and two cases of the persistence of a 

 left posterior cardinal vein in Axolotl. Joseph himself (loc. cit.) des- 

 cribes a case in a female Salamander in which the left posterior car- 

 dinal vein was persistent. 



One further point is to be noted with regard to these abnorma- 

 lities connected with post-caval, posterior cardinal, or renal-portal 



1) The heart of this frog w^as also abnormal, being in a primitive unflexed 

 '.condition somewhat similar to the two already described (8). 



