300 



HISTOGENESIS 



f.c. 



mu 





S.C. 



mes. 



FIG. 289. Two stages in the development of smooth muscle fibers; A, from the esophagus of a i,s 

 mm. pig (McGill); B, a longitudinal section of the esophagus of a 27 mm. pig (after McGill in 

 Lewis-Stohr). b, b.m., basement membrane; e, epi, epithelium; f.c., myoglia fibrils; g.s., granules coa- 

 lescing; h. s., homogeneous fibers; mes., mesenchyma; mm., muscularis mucosae; mu., muscle cell; ., 

 nerve cells; s.c., circular smooth muscle cut across; s.l., longitudinal smooth muscle cut lengthwise. 



