600 



Gideon S. Dodds. 



EXPLANATION OF FIGURES 



1-11 are diagrammatic representations of cross-sections of embryos of succes- 

 sive stages through the region of the germ-cells. The position of germ-cells is 

 shown by solid black circles. All these drawings were outlined with the aid of a 

 camera lucida and reduced to a magnification of 110 diameters. 



1. Cross section of embryo of stage 6. X 110. 



2* Cross section of an embryo of stage 6 a little more advanced than the on 

 shown in fig. 1. X 110. 



3. Cross section of embryo of stage 7. X 110. 



4. Cross section more advanced embryo of stage 7. X HO. 



5. Cross section of embryo of stage 8. X 110. 



6. Cross section of embryo of stage 9. X 110. 



7. Cross section of embryo of stage 10. X HO. 



8. Cross section of embryo of stage 11. X 110. 



9. Cross section of embryo of stage 12. X HO. 



