586 J. T. WILSON AND J. P. HILL. 
Fie. 21.—U. J., H. S. Cutting the oral epithelium at the point marked 
0.:6.- X90: 
Fic, 22.—U. J., H. S. At a somewhat higher level than Fig. 21. x 90. 
Fie. 23.—U. J., C. S. Through the third incisor (2) of an early fcetus of 
Dasyurus viverrinus. x 330. 
Fic. 24.—U. J., C. §. dp. x 180. 
Fie. 25.—U. J., H. S. Molar region at a higher level than Fig. 22. x 90. 
Fic. 26.—U. J., H. S. m+ at a higher plane than Fig. 25. x 90. 
Fie. 27.—U. J., C. S. Middle region m2. x 130. 
Fie. 28.—U. J., C. S. m+ in the third section behind Fig. 27. x 180. 
Fic. 29.—U. J., C. §. Posterior region of m1. x 120. 
Fig. 30.—U. J., C. S. Dental lamina just behind m2. x 120. 
Fie. 31.—U. J., C. S. Dental lamina five sections behind Fig. 30. x 120. 
Fie. 32.—U. J., C. 8. Dental lamina in region of future m2, and just in 
front of its termination. x 120. 
Fic. 33.—Z. J., C. 8. iz and diz. x 280. 
Fie. 34.—L. J., C. §. Anlagen of tg andiz. x 120. 
Fic. 35.—Z. J., H. 8. Anlage of tz and zz. x 90. 
Fie. 36.—Z. J., H. S. Nearer the oral epithelium than Fig. 35. x 90. 
Fic. 37.—L. J., C. S. Anlage of permanent <, with deeply cupped enamel- 
organ of dz. x 210. 
Fig. 38.—Z. J., C. 8. Anlage of pz. x 150. 
Fie, 39.—L. J., C. 8. dpz. X 280. 
Fie. 40.—Z. J., C. 8S. dpz, seven sections behind Fig. 39, showing the 
differentiation of cusps. x 180. 
Fic. 41.—L. J, C. 8S. mz. x 120. 
Fic. 42.—Z, J., C. §. Dental lamina behind enamel-organ of mz. x 1920. 
Stace IV. 
Fic. 43.—U. J., €. S. Dental lamina in front of 22. ca. Common Anlage 
of lip-groove and dental lamina proper. xX 120. 
Fie. 44.—U. J., C. 8. i+. ep. Epithelial ingrowths (see text). x 120. 
Fic. 45.—-U. J., C. S. i2 three sections behind Fig. 44. x 120. 
Fic. 46.—U. J., C. 8. i+ five sections behind Fig. 45. x 120. 
Fic. 47.—U. J., C. S. ¢ with remains of d. x 100. 
Fic. 48.—U. J., C. 8. dp® passing through the protocone. x 130. 
Fie. 49.—U. J., H. 8. Through the region between p2 and m2. For ex- 
