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ALBERT KUNTZ 



from the distal ends of the spinal ganglia diagonally through the 

 mesenchyme toward the lateral surfaces of the aorta, where they 

 terminate in loose cell-aggregates which constitute the anlagen 

 of the ganglia of the sympathetic trunks (fig. 1). 



The cells which thus become separated from the cerebro-spinal 

 nervous system and migrate peripherally before the spinal nerves 



Fig. 1 Transverse section through the trunk region of an eight-day embryo of 

 Thalassochelys caretta. X 210. Ao., aorta; M.C., path of cells migrating into 

 sympathetic anlage; M.P., muscle plate ; Nc, notochord; Sp.G., spinal ganglion; 

 Sy., anlage of symphathetic trunk. 



arise may be distinguished from the cells of the mesenchyme by 

 their slightly deeper stain and by the characteristic chromatin 

 structure of their nuclei. The cells in these tracts leading from 

 the spinal ganglia into the cell-aggregates constituting the anlagen 

 of the sympathetic trunks are not closely aggregated nor is there 

 any evidence that they are embraced in syncytia. Although 

 mitotic figures in their various phases occur frequently along 



