124 



PROF. G. B. HOWES ON THE AZYGOS 



[Feb. 21, 



of the adult. In Bombinator, however, despite the persistence of 

 both renal portal and azygos veins, this continuity is eventually lost. 

 In the specimen of the Common Frog under consideration it persisted. 



a.c 



Fig.l. 



;« Fig.2 



7:a 



od-'-— 



Thu venous system of an adnlt of Bana temporaria ( $ ), showing a persistent 

 azTgos (posterior cardinal) vein. 



Fig. 1. Ventral aspect. 



The vena cava inferior in part removed, and the left kidney turned slightly 

 inwards to display its external dorsal border. 



Pig. 2. Left kidney, dorsal aspect. Magnified 1^ times. 

 a.c. Vena cava superior ; c.p, azygos (posterior cardinal) vein ; d.l, dorso- 

 lumbar vein ; il, iliac vein ; od, oviducal veins ; ov, ovarian veins ; 'p-<^, cut ends 

 of vena cava inferior; r.fl, vence renales advehentes; s.v, sinus venosus; ?(/•, 

 ureter. 



and the anastomosing trunk received (or gave oflF) renal branches. 

 This fact is the more surprising, in that in Pelobates the separation 

 takes place before metamorphosis, at a period when the anterior 

 segment of the cardinal vein is but feebly developed '. 



1 Hochstetter, iv. p. 162. 



