CEMENT 



291 



FIG. 184. Tooth of Bettongia, showing communication of dentinal 

 fibrils with periodontal membrane. ( x 250.) 



FIG. 185. Lacunal cells within the lacunas of cement (Bettongia), 

 showing communication of dentinal fibrils with canaliculi. The lacunal 

 cell is seen to occupy the whole lacuna. Two nucleoli are seen within the 

 dark-stained nucleus. ( x 350.) 



U 2 



