TOOTH DEVELOPMENT — DASYPUS NOVEMCICNTUS 681 



12. Between the first functional back tooth and the posterior 

 end of the premaxiha, there exists an extensive diastema. The 

 dental lamina extends through this region but degenerates with- 

 out warning giving rise to tooth germs. 



13. In the extreme posterior end of the premaxilla there occur 

 from three to five upgrowths of the oral epithelium. These be- 

 come detached from their place of origin and form cysts, the con- 

 tents of which resemble an oral epithelium which has become 

 horny like the peripheral layer of the stratum corneum. These 

 cysts evidently represent tooth anlagen which have lost all like- 

 ness to enamel organs and behave as if they were still on the sur- 

 face of the jaw. 



