300 



ALBERT KUNTZ 



assochelys caretta during the twelfth or the thirteenth day of 

 incubation, the vagus trunks appear as conspicuous fiber-bundles 

 lying a little above the level of the trachea. In some sections 

 short fibrous branches may be traced from the vagus trunks. 

 Cells become separated from the vagus trunks and wandering 

 out along these fibrous branches escape from their growing tips 

 and become arranged in a broken ring encircling the oesophagus 

 (fig. 10, M.S. P.). Cells maybe observed apparently wandering 

 out from the vagus trunks also in sections in which fibrous branches 



\6. 



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i!>C-i 



x:/ ''r::rfel^ 



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i«'. 



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Fig. 10 Transverse section through the oesophagus of a thirteen-day embryo 

 of Thalassochelys caretta. X 140. M.S. P., anlagen of myenteric and submucous 

 plexuses; Oe., oesophagus; 7'., trachea; Vag., vagus nerves. 



are not apparent. At this stage small groups of sympathetic 

 cells may be traced completely round the oesophagus dorsally, 

 while on the ventral side similar cell-groups may be traced mes- 

 ially from the vagus trunks into the area between the oesophagus 

 and the trachea where they become lost in the deeply staining 

 tissues in that area. The vagus trunks may be traced poste- 

 riorly nearly to the stomach, and as far as they may be traced 



