240 PAULINE H. DEDERER. 



PLATE III. 



FIG. 8. Group of seven ectoderm cells, free from overlying mesenchyme. 

 A bilobed nucleus is visible in one cell. 



FIG. 9. Group of mesenchyme cells forming a membrane with relatively 

 small intercellular spaces. Mitochondria are visible in the form of threads and 

 granules. 



FIG. 10. Portion of outgrowth showing striations in ectoderm cells. Nuclei 

 and cytoplasm of mesenchyme cells are visible as dark masses upon the ectoderm. 



