504 



INDEX. 



YELK, i. 135 



arteries, i. 395 



cavity, i. 138 



duct, i. 338; ii. 1G8 



formative, i. 216 



membrane, i. 138 



~ nutritive, i. 216 

 sac, i. 337 



Yelk veins, i. 395 

 vessels, i. 395 



Zona, pelludda, i. 135 

 Zonaplacentalia, ii. 162, 187 

 Zoophyta, i. 246 ; ii. 73 



