layer of 
= ameloblasts 
inner layer 
of enamel 
Fig. 7 Portion of cross-section of lower incisor with enamel-organ, pre- 
pared by the petrifaction method, showing the decussation of the enamel-rods 
in the inner or plexiform layer and their parallel arrangement in the outer or 
fibrous layer. X 350. 
Fig. 8 Small piece of enamel, showing the rods of the inner or plexiform 
layer running in two directions nearly at right angles to one another. X 350. 
56 
