258 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 



Fig. 34 shows the condition of the lamina eight sections behind that shown in 

 Fig. 35, still in the incisor region. The sections were 7.5 /i. thick. 



Fig. 35 is the anterior face of a section through the incisor region, showing the 

 condition of the dental lamina in the upper jaw. 



Fig. 36. The dental lamina of Fig. 28 as it appears when highly magnified. 



Fig. 37. A portion of the section outlined in Fig. 29a. The central cells of 

 the germ have become vacuolated. 



