318 MICROSCOPIC ANATOMY OF THE TEETH 



cement, and are always well separated from the inner 

 epithelial layers. 



The other noticeable appearance is the presence of 

 a fenestrated membrane-like expansion which is seen only 

 opposite the sulcus between the cusps of the molar tooth 

 (fig. 207). It is difficult to decide what this membrane repre- 

 sents ; if it forms a portion of the inner layer of Nasmyth's 

 membrane it is difficult to account for its fenestrated nature, 

 as the clear layer in preparations of the membrane is never 



FIG. 206, Calcified masses within the follicle at 

 its centre. ( x 50.) 



fenestrated but entire. The openings in the membrane are 

 of very unequal sizes, and the whole structure appears to 

 be of a stouter and tougher nature than the thin fenestrated 

 membrane which can be raised from the enamel surface, 

 especially in marsupials. 



At the point of junction with the tooth, the follicle is 

 narrow and composed of strong connective tissue. Epithelial 

 cells are present in this narrow part of the follicle, and can 

 be traced upwards to its coronal portion, where they are in 

 great abundance, and can be seen in all stages of growth 

 and degeneration. 



It is noticeable that the epithelial masses appear to have 



