So r&A THER. 



EXPLANATION OF FIGURES. 



FIG. i. Median sagittal section of the anterior portion of an embryo sur- 

 rounding about 245 of the egg's circumference. About 148 hours, x 60. 



FIG. 2. Median sagittal section of the anterior portion of an embryo a few 

 hours before hatching time. About 160 hours. X 60. 



FIG. 3. The base of the thalamencephalon, the foregut, and the stomodaeum 

 of the same section under stronger magnification, x 1 90. 



FIG. 4. Median sagittal section through the anterior portion of a larva soon 

 after hatching, early in the eighth day. x 60. 



FIG. 5. The roof of the mouth and the hypophysis of the same section more 

 highly magnified. X 190. 



FIG. 6. Transverse section through the brain and hypophysis of a larva about 

 eight days old. x 60. 



FIG. 7. Median sagittal section through the hypophysis and base of the 

 thalamencephalon of a larva nearly nine days old. < 190. 



FIG. 8. Transverse section through the hypophysis and base of the infun- 

 dibulum of a larva during the tenth day. x 190. 



FIG. 9. Median sagittal section through the hypophysis and infundibulum of 

 a larva ten days old. x 60. 



FIG. 10. Transverse section of the hypophysis and base of the infundibulum 

 of a larva ten days old. X 190. 



FIG. n. Median sagittal section through the hypophysis and infundibulum of 

 a larva fourteen days old. x 60. 



FIG. 12. Median sagittal section through the hypophysis and adjacent parts 

 of a larva about the same age as the preceding, x 190. 



FIG. 13. Transverse section of the hypophysis and infundibulum of a larva 

 about fifteen days old. x 60. 



FIG. 14. Transverse section through the hypophysis and infundibulum of a 

 larva between twenty-two and twenty-six days old. x 60. 



FIG. 15. The hypophysis of the same section more highly magnified. X 215. 



FIG. 16. Median sagittal section through the hypophysis and infundibulum of 

 a larva between thirty and thirty-five days old. x 60. 



FIG. 17. Transverse section through the hypophysis and infundibulum of a 

 larva of the same age as the preceding. < 60. 



FIG. 18. A nearly horizontal section through the hypophysis of a larva about 

 thirty days old. X 105. 



