244 The Development of the Yena Cava Inferior 



V. Sp., subcardinal vein. 



V. Sc. i., subcardinal vein, inferior division. 



V. Sc. w., subcardinal vein, branch from Wolffian body. 



V. U. d., right umbilical vein. 



y. Z7. s., left umbilical vein. 



W. B., Wolffian body. 



X., cross connection betv^^een subcardinals. 



Y., cross connection betvs^een posterior cardinals. 



