472 



INDEX 



/ 



pouches, early development of, 175- 

 178; pouches, fate of, 307, 308 



Vitelline membrane, 10, 30, 31 



Vitreous humor, 275 



ongm 



White matter of spinal cord, 



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 

 ninetv-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 



