CIRCULATORY ORGANS. 



301 



FIG. 307 . Development of posterior veins of rabbit, after Hochstetter. C and D repre- 

 sent only the hinder part of the whole shown in .4 to C. In B the veins for the postcaval- 

 subcardinal system have tapped the postcardinal veins, which in C have lost their connec- 

 tion with the anterior part and empty now through the postcava exclusively. In E the 

 left posterior postcardinal is entirely lost, i, ischiadic vein; ie, external iliac; i, jugular; 

 mt, metanephros (kidney); p, postcava; pc, postcardinal; s, subclavian; sc, subcardinal: 

 sr, suprarenal; u, ureter. 



A 



B 



FIG. 308. Development of the anterior veins of a mammal. A, earlier stage, to be 

 compared with fig. 307 C; B, definitive condition of adult, a, azygos; c, coronary; e, i, 

 external and internal jugular; ha, hemiazygos; il, iliac; in, innominate; p, postcava; pc, 

 postcardinal; prc, precava (superior vena cava); si, superior intercostal veins. 



