3°° 



HISTOGENESIS 

 A 



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Fig. 289. — Two stages in the development of smooth muscle fibers; A, from the esophagus of a 13 

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

 Lewis-Stohr). 6, b.m., basement membrane; e, epi, epithelium; f.c, myoglia fibrils; g.s., granules coa- 

 lescing; h.s., homogeneous fibers; mes., mesenchyma; mm., muscularis mucosas; 11111., muscle cell; «., 

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



