72 



LEONARD W. WILLIAMS 



dorsal lamella. A small stalk of mesenchyma still binds the 

 sclerotome to the essentially complete dermomyotome and pre- 

 vents the final fusion of the edges of the myotome and cutis 

 plate or dermatome. The nuclei of the lower part of the myotome 

 are distinctly larger than those of its upper or medial edge. 

 Mitoses are abundant in all parts of the mj^otome. 



D.M 



O.L. 



RA 



Text fig. 1. Model of the left somite of the second segments of an embryo 

 of eighteen segments. The medial, anterior and part of the dorsal surface are 

 seen. X 400. H. E. C. no. 146G. 



The dermomyotome is barely complete when its disintegration 

 begins. This process, however, is only slightly indicated at this 

 time in a small area just lateral to the center of the cutis plate. 



