EXPLANATION OF FIGURES. 



Plate II. 



Figs. I and IV a. First indication of a vesicle shown by the pro- 

 tuberance of a single epidermal cell. 



Figs. II, III, and IV, Successive stages in the development of the 

 vesicle. 



Fig. V, Mature vesicle from a leaf showing the drawn out apex of 

 vesicle ; seen in transverse section. 



Fig. VI, Mature vesicle from stem. 



Fig. VII, Longitudinal section through the base of a vesicle on stem, 

 showing the pits at its base. 



Fig. VIII, Pits on the base of a vesicle, seen from above. 



