PLATE 2 



EXPLANATIOX OF FIGURES 



5 Dissection of an 11.75-mni. opossvnn embryo to show the positions and rekx- 

 tions of the viscera in the body. The stomach and intestines of this embrj'o — 

 one a few hours before ]>irth — are shown in figures 3, 7, and 9. These organs were 

 then embedded and sectioned. Embrvo no. 1.54. X 12. 



360 



