472 



INDEX 



pouches, early development of, 175- 

 178; pouches, fate of, 307, 308 



Vitelline membrane, 10, 30, 31 



Vitreous humor, 275 



White matter of spinal cord, origin 



of, 239, 241 

 Wing, origin of skeleton of, 434, 436 

 Wolffian body (see mesonephros) • 

 atrophy, 380, 382, 401; sexual 

 and non-sexual portions, 396; at 

 ninety-six hours, 379; on the 

 sixth day, 382; on the eighth day, 

 382, 383; on the eleventh day, 385 



Wolffian duct, 191, 193, 194, 391, 401 



Yolk, 17, 19; formation of, 29 



Yolk-sac, 143, 225-231; entoderm 

 of, 50; blood-vessels of, 227-230- 

 septa of, 225-227; ultimate fate 

 of, 230, 231 



Yolk-spheres, 19, 20 



Yolk-stalk, 132, 225 



Zona radiata, 10, 30, 31 

 Zone of junction, 52, 57 

 Zones of the blastoderm, 127-129 



