76 K. MITSUKURI. 



lying between the dorsal aorta and the caudal vein, in the 

 region of the posterior end of the kidneys." The other, 

 named the suprarenal bodies^ consists of '^ a series of paired 

 bodies, situated dorsal to the cardinal veins on the branches 

 of the aorta, and arranged segmentally/^ The former was 

 believed by him to be developed from the niesoblast, and to 

 have nothing to do with the latter, which are formed out of 

 sympathetic ganglia, and remain in close connection with 

 them throughout life. At that time Mr. Balfour was inclined 

 to consider the suprarenal bodies homologous with the organ 

 that goes under that name in the higher vertebrates, and the 

 interrenal body, an altogether independent structure. He 

 therefore agreed, to some extent, with the earlier view of 

 Leydig. It will be seen that he has since modified his 

 opinions. 



Braun^ studied the anatomy and development of the supra- 

 renal bodies in Reptilians. In that class they are formed of 

 two parts, viz. (1) masses of brown cells placed on the dorsal 

 side of, and closely applied against, (2) irregular cords of 

 cells, so full of oil globules that nuclei are altogether 

 invisible in the fresh state. Tne first is derived from the 

 sympathetic ganglia, and the second from the ordinary 

 niesoblast. Here, clearly, the nervous cells, having the cha- 

 racteristic reaction of being stained brown by bichromate of 

 potash, are homologous with the medullary, and the irregular 

 cords containing oil globules, with the cortical part of the 

 Mammalian suprarenals. 



Brunn^ makes an interesting statement in regard to the 

 suprarenal bodies of birds. According to him the cells 

 stained brown by bichromate of potash — i. e. the elements 

 composing the medullary part of the mammalian suprarenals 

 — are scattered throughout the organ between irregular cords 

 of cells, which are like those composing the cortical part of 

 the higher type. 



Summing up these observations Mr. Balfour says, in his 

 'Comparative Embryology^ (vol. ii, pp. 548-9), *' The 

 structure and development of what I have called the in- 

 terrenal body in Elasmobranchii so closely correspond with 

 that of the mesoblastic part of the suprarenal bodies of the 

 Keptilia, that I have very little hesitation in regarding them 

 as homologous ; while the paired bodies in Elasmobranchii, 



^ M. Braun, — " Bau u. Entwick. d. Nebennieren bei Reptilien," 

 ' Arbeit a. d. zool.-zoot. Institut, Wiirzburg,' vol. v, 1879. 



' A. von Brunn. — " Ein Beitrag zur Kentniss des feineren Baues und 

 Entwicklungsgeschichte der Nebennieren," ' Archiv fiir mikros. Anat.,' 

 vol. viii, 1872. 



