84 



INDIVIDUALITY IN ORGANISMS 



and the shading indicates in a general way the disap- 

 pearance of the vacuoles and the filling of the cells with 



a, 



a 



Figs. 35-37. — Metzgeria, a liverwort: Fig. 35, portion of pro- 

 thallium, showing midrib and apical regions, a, a; Fig. 36, cell structure 

 of growing tip, showing apical cell, a, and gradient in cell size; Fig. 37, 

 cell structure of an adventitious bud, showing apical cell, a, and gradient 

 in cell size (Figs. 36, and 37 from Goebel). 



protoplasm. A gradient in cell size and protoplasmic 

 condition appears in both cases, in Fig. 38 from the 

 center to the periphery of the region involved and in 



