INDEX. 





Wolffian ducts, 149, 151 

 Wood-pareuchyma, 10, 81 



Xylem, 10, 80, 81 

 Yolk, 146, 147 



Yolk-stalk, 152 



Zoochlorella, 55 

 Zooglcea, 46 

 Zoospore, 28, 29 

 Zyguerna, 50 



163 



