352 



Messrs. B. Moore and S. Vincent. 



primitive vessels : the anterior ventral aorta, the fourth left cephalic 

 aortic arch, the fused portions of the primitive dorsal aortas, and in 

 some mammals the fused dorsal ends of the caudal arches. 



The permanent adult aorta, in so far as it is formed by the primi- 

 tive dorsal aorfcae, ends posteriorly either at the bifurcation into the 

 two common iliac arteries or at a point corresponding to this bifurca- 

 tion, when by more extensive fusion involving the dorsal parts of the 

 secondary arches there are no common iliacs, and the external and 

 internal iliac arteries appear to arise directly and separately from the 

 aorta3. In each case the continuity of the primitive aorta is inter- 

 rupted, and the primary caudal arches are replaced by secondary 

 caudal arches, after which the continuations of the aorta are repre- 

 sented by the vessels into which the secondary caudal arches are 

 ultimately transformed. 



Our conclusions are further supported by more extended observa- 

 tions on the anatomy of the posterior end of the aorta, and its 

 terminal branches in mammals, and on the abnormalities they present 

 in man, a general account of which is included in the memoir. 



' Further Observations npon the Comparative Chemistry of 

 the Suprarenal Capsules, with Remarks upon the Non- 

 existence of Suprarenal Medulla in Teleostean Fishes." 

 By B. Moore, M.A., Sharp ey Scholar, University College, 

 London, and Swale Vincent. M.B. (Loud.), British Medical 

 Association Research Scholar. Communicated by Professor 

 E. A. Sohafer, F.R.S. Received January 27,— Read 

 February 10, 1898. 



(From the Physiological Laboratory, University College, London.) 



In a previous communication* we have shown that the paired 

 segmental suprarenals of Elasmohranchs contain a chromogen which 

 gives the same reactions as that of the medullary portion of the supra- 

 renal capsule of higher vertebrates, while the inter-renal body in the 

 same order of fishes contains no such chromogen. These facts were 

 put forward in support of views previously expressed, f that the 

 segmental bodies corresponded physiologically, as well as morpho- 

 logically and histologically, to the medulla of mammalian suprarenal, 

 while the infcer-renal corresponded to the cortex. 



Now it has been already pointed outj that the known suprarenal 



* ' Eoy. Soc. Proc.,' 1897 (read December 11, 1897). 



f Swale Vincent, ' Roy. Soc. Proc.,' vol. 61, p. 64, and ibid., vol. 62, p. 176, and 

 other references (given in these two papers) . 

 X Swale Vincent, loc. ext. 



