84 



ALBERT KUNTZ 



sections of columns of such cells which have penetrated deeply* 

 into the vascular spaces between the aggregates of the cortical 

 cells. 



In embryos forty-three days old, the adrenals have become more 

 intimately associated with the renal organs and are located on 

 the ventro-mesial surfaces of the latter in approximately the same 

 position which is maintained by them throughout adult life. A 

 larger proportion of the cells of sympathetic origin have pene- 

 trated into the vascular spaces between the aggregates of the 

 cortical cells. The distribution of the cortical and the chromaffin 





»■■/'?* 







v's (S? co "*sSi&:« 



r^£s^ 



Fig. 9 Transverse section through adrenal in a forty-three-day embryo of 

 Thalassochelys caretta. X 75. cc, chromaffin substance; co, cortical substance; 

 mc, mesenchyme cells; vs, vascular spaces. 



substance, therefore, approaches closely the distribution of these 

 substances in the mature gland. Fig. 9 is introduced to illustrate 

 the distribution of the cortical and the chromaffin substance and 

 their relation to each other in an embryo forty-three days old. 



Neither during embryonic development nor in the adult con- 

 dition do the vascular spaces between the aggregates of cortical 

 cells, into which the chromaffin cells penetrate, show well defined 

 walls which are characteristic of arteries or veins, but are lined 

 by a single layer of flattened epithelial cells (fig. 8, vs). That these 

 spaces are blood vessels, however, is indicated by the presence in 



