472 
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, 456 
Wolffian body (see mesonephros) ; 
atrophy, 380, 9382, 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 
INDEX 
Wolffian duct, 191, 193, 194, 391, 401 
Yolk, 17, 19; formation of, 29 
Yolk-sae, 148, 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, 182, 225 
Zona radiata, 10, 30, 31 
Zone of junction, 52, 57 
Zones of the blastoderm, 127-129 
