Scottish National Antarctic Expedition : Observations on the Anatomy of the 

 Weddell Seal (Leptonychotes Weddelli). By David Hepburn, .M.D., (A.M., 

 F.R.S.E., Professor of Anatomy, University College, Cardiff (University of Wales). 

 Part II.* 



(MS. received December 4, 1911. Ri-ad January 8, 1912. Issued separately January 19, 1912.) 



GENITO-URINARY ORGANS. 



In my former contribution I gave a general summary of the animal under considera- 

 tion, and discussed in detail the peritonea] arrangements of its abdominal cavity and 

 the naked-eye anatomy of its alimentary organs. In the present paper 1 shall give an 

 account of the geuito-urinary system. 



The kidneys were situated on each side of the dorsal mesial mesentery. Each was 

 covered on its ventral aspect by the peritoneum forming the dorsal wall of the greater 

 peritoneal sac. The right kidney was quite free from contact with the liver and the 

 duodenum, while the left kidney was equally free from contact with the spleen. Both 

 kidneys were therefore situated well back towards the pelvic end of the abdominal 

 cavity. Each kidney measured 5 inches in the longitudinal diameter and 2 inches 

 in the transverse diameter. The hinder or caudal end of each reached a point two 

 inches from the pelvic inlet, which, as formerly described, was narrow ami well defined 

 by the course of the hypogastric (umbilical) arteries. 



The surface of the kidnev indicated lobulation, but the lobules were not separated from 

 each other. The hilum was placed ventro-mesially, and at its point of emergence from the 

 surface of the kidney the ureter was nearer to the caudal than to the cephalic end of the 

 organ. On opening up the hilum, the ureter was seen to result from the union of two main 

 tributaries, each of which, in its turn, was formed by the junction of several smaller root- 

 lets, which corresponded more or less closely in number to the number of the kidney 

 lobules. There was no distinct pelvis to the ureter, which was gradually formed by the 

 junction of smaller ducts in the manner indicated. Nevertheless, the widest point of 

 the ureter was found at the junction of its two main tributaries. The ureter and its 

 chief tributaries lay on the ventral (anterior) aspect of the renal vessels, and not on their 

 dorsal (posterior) aspect, as is the case in man. 



The size of the ureter suggested a vessel about half the diameter of an average 

 human radial artery. The ureter followed a course along the dorsal wall of the abdomen 

 towards the pelvic inlet ; and half an inch beyond the termination of the abdominal 

 aorta, or, in other words, at the point where the common iliac artery divided into its 

 external and internal branches, the ureter crossed to the mesial side of the internal iliac 

 and hypogastric arteries, and continued its course along the margin of the pelvic inlet. 

 In this position the ureter and the hypogastric artery were both in their turn crossed 



* Part I. was published in the Trans. Roy. Soc. Edin., vol. xlvii., pt. i. (No. 3), 1909. 

 (REPRINTED FROM THE TRANSACTIONS OF THE ROYAL SOCIETY OF EDINBURGH, VOL. XLVIII., PP. 191-194.) 



