Fig. 7. Zone A, ruffled border. Bone matri.x to left. Note pinosoiiu i /') at 

 top, and others in varying section plane (horizontal arrows). Finer channels 

 (vertical arrows) also lead off from matrix edge. Demineralized collagen (F) 

 can be seen between cytoplasmic folds. ( X 70,000.) 



506 



