SYSTEM AND SUriUREXAL BODIES IN THE SPARROW. 



761 



Text- figs. 18 & 19, from Sparrow 53, show tlie relations of the 

 sympathetic and the suprarenal body. The latter now surrounds 

 the internal Wolffian vein, while the sympathetic chains dorso- 

 lateral to the aorta are largely developed, and give rise to masses 

 of cells which pass from them to the cortical primordia. The 

 point of entry of these cells seems usually to be on the mesial 

 face of the suprarenal body (text-tig. 18), but in text-fig. 19 

 there is apparently a dorsal -entry. 



Text-figure 17. 



MC. 







C/? 



mmm^::m. 







ei?-# 



WW 



-c.s 



Af.S 



Transverse section of Sparrow 5, showing first signs of invasion ot cortex by 

 medullary colls (M.C.) from the primary sympathetic. Lettering as in text-fig. 13. 



It is noteworthy that these contributions of the sympathetic 

 to the suprarenal all arise from the primary sympathetic cords, 

 which apparently proliferate them at about the same time as 

 they are giving rise to the definitive cords, by the outgrowth 

 of dorso-lateral branches, as described above. We have not 

 attempted a detailed description of the changes which occur in 

 the development of the suprarenal bodies, as these have been 



