756 



A. SUBBA RAU AND P. 11. JOUNSOX ON THE NEKVOUS 



sections, of Sparrow 13 at the points marked a-a, b-b in text- 

 fig. 9 D. The sections are only 56 /u apart, but the diflerence is 

 very marked. The section shown in text-fig. 10 a passes through 

 the dorso-lateral processes of the primary sympathetic chain, and 

 shows their relations to the surrounding structures. They lie 

 between the segmental artery and vein, and extend dorso- 

 latorally from the aorta to a point about halfway towards the 



Text-figure 12. 



A/tc. 



S.Sc. 







.,:gj-.. . 



i;r*<r-^ 





'■■<9 . ''i 



fPS.C. 







Transverse section tlirougli Spuvrow B at point ninrkcd i;-ii in fig. 9 G. Tlio secou 

 (iary syiupathotic chuiu (S^bV.) is closely opposed to the spinal nerve. 



origin of t])e ventral roots. The section in text-fig. 10 fc, on the 

 other hand, shows the primary sympathetic as a comparatively 

 small strand close to the aorta. This section passes through the 

 myotome and the dorsal root ganglion, while that shown iu text- 

 fig. 10 a passes between the somites. 



Text-figs. 11 it 12 drawn from sections of Sparrow B, at points 



