1889.] ON THE LEFT CARDINAL VEIN IN THE FROG. 145 



6; ?. 



millim. millim. 



Total length 228 200 



Head 28 28 



Width of head 20 20 



Body 76 72 



Fore limb 41 39 



Hind, limb 6.5 57 



Tail 114 100 



From the Sierra de Uspallata and the desert west of Catamarca. 

 Differs from U. torquatus, to which it is closely allied, in the 

 longer head, shorter digits, and shorter tail. 



EXPLANATION OF PLATE XV. 



Fig. 1. Gyiimodactylus korridus, with enlarged view of chin. 

 2. Urostrophns scapulatus j , with upper view of head. 



3. On the occasional Persistence of the Left Posterior 

 Cardinal Vein in the Frog, with Remarks on the 

 Homologies of the Veins in the Dipnoi. By W. Newton 

 Parker, Ph.D., F.Z.S., Professor of Biology in the 

 University College of South Wales and Monmouthshire. 



[Eeceived March 8, 1889.] 



According to the recent researches of Hochstetter ', the postcaval 

 vein arises in part independently (" Leberabschnitt "), and in part 

 from that portion of one (Amniota) or of both (Amphibia) posterior 

 cardinal veins wliich receive the vense renales revehentes (" Uruieren- 

 abschnitt "). The part of the cardinals which lies anterior to the 

 kidneys either disappears, or else gives rise to the azygos (and hemi- 

 azygos) veins. 



In the Salamander, and apparently in most TJrodeles, the right 

 and left azygos are present normally, while in the greater number of 

 Anura they disappear entirely in the adult. In Bombinator, how- 

 ever, they persist (Gotte ", Hochstetter), and this is also the case 

 occasionally in Alytes and Discoglossus^. 



Howes has recently described an interesting case of the persistence 

 of the left azygos in a female of the Common Frog {Rana tempor- 

 aria) ^, the vessel being of large calibre and continuous anteriorly with 



^ "Beitrage zur vergl. Auat. u. Eutwickeliingsgeschichte des Veuensyatems 

 der Amphibian und Fisohe," Morphol. Jahrbuch, Ed. xiii. 1887-8. " Ueber die 

 Bilduiig d. bintereu Hohlvene bei den Saugethieren," Anat. Anz. ii. Jahrg. 1887. 

 " Beitrage zur Entwickelungsgeschichte des Venensystems der Amnioten," 

 Morphol. Jahrbuch, Bd. xiii. 1887-8. 



^ Entwickelungsgeschichte der Unke. 



^ G. B. Howes, "On the Azygos Vein in the Anurous Amphibia," Proc. Zool. 

 Soc. 1888, p. 122. 



* Log. cit. 



