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ALBERT KUNTZ 



be definitely determined. In the early stages, single sympathetic 

 cells could not be traced in the dense tissues of the walls of the 

 digestive tube. It is difficult, therefore, to determine whether or 

 not such cells migrate posteriorly in the walls of the digestive 

 tube, as is the case in mammalian embryos. It is probable, how- 

 ever, that such is the case. On the other hand, it is probable that 

 some of the cells which take part in the development of the myen- 



m , s P 



|. IP--^:/*. 



Fig. 7. Transverse section through the oesophagus and the vagi of an embryo 

 of the chick (144 hours incubation), X 80. ao., aorta; m.s.p., cells giving rise to 

 myenteric and submucous plexuses; oe., oesophagus; t., trachea; vag.n., vagus 

 trunks. 



Fig. 9. Transverse section through the oesophagus and the anlagen of the car- 

 diac plexus of an embryo of the chick (144 hours incubation), X 80. a.c, atrial 

 cavity; a.s., atrial septum; car. p., anlagen of cardiac plexus; m.s.p., cells giving 

 rise to myenteric and submucous plexuses; oe., oesophagus; vag.n., vagus trunks. 



teric and the submucous plexuses in the posterior region of the 

 intestine wander out from the ganglion of Remak. There is no 

 evidence of cells entering the sympathetic plexuses in the walls of 

 the digestive tube from the sympathetic trunks or from the pre- 

 vertebral plexuses, except through the ganglion of Remak, until 



