357 



/ nt 



no venae renales advehentes, combined with an entire absence of the 

 anterior part of the post-caval. It presents however several pecul- 

 iarities which render it worthy of description. There is an unpaired 

 vein which runs forward 

 along the urostyle to 

 the level of the poste- 

 rior end of the kidneys, 

 where it turns at right 

 angles to the left, and 

 enters the persistent 

 posterior cardinal just 

 before the latter 

 becomes attached to 

 the lateral border of 

 the kidney. This un- 

 usual vein apparently 

 represents the per- 

 sistent caudal vein, 

 which accordifig to 

 HocHSTETTER (9) forks 

 to form the posterior 

 cardinals. Its trans- 

 verse portion would 

 thus represent the 

 original renal portal 

 (Jacobson's vein) which 

 is afterwards joined by 

 the iliac, and which 

 does not persist in the 

 normal frog. The con- 

 tinuation of the inter- 

 renal vein runs into 

 the posterior cardinal 

 anterior to the kidney; so that it diifers from the previous case, 

 and is somewhat similar to the specimens described by Shore (19) 

 and Woodland (22) only it is in a still more primitive condition. 

 From this point the course of the posterior cardinal is similar to 

 that of the frog already described, save that the curvature is still 

 more marked and there is no conspicuous dilatation of the innominate ^). 



1) The arrangement of the anterior vsina on the right presents no 

 abnormality. It is interesting to notice however that the relative sizes 

 of the factors of the musculo-cutaneous vein are different from those in 



Fig. 2. Diagram of Venous 

 System of Specimen B. *S^. Sper- 

 matic, >S'. V. Sinus Venosus, U. Pro- 

 bably peraistent caudal. Other letters 

 as in Fig. 1. 



A. Dorsal surface of right kidney 

 to show the distribution of the renal 

 portal vein. 



A. 



