64 PROF. DAVID HEPBURN 



by the vas cleferens, which now assumed the mesial position to both of the others. Up to 

 this point the ureter had not entered the pelvic cavity, and about three-quarters of an 

 inch onwards, that is, in the direction of the tail, the ureter, still lying close to the pelvic 

 brim, entered the lateral aspect of the urinary bladder, travelling between the folds of 

 a lateral vesical mesentery or peritoneal ligament. Thus, as a consequence of the great 

 obliquity of the pelvic inlet, the ureter was able to reach the bladder by skirting the 

 pel vie brim, and at no point did it require to enter or sink into the interior of the pelvis. 



The urinary bladder was placed mesially, and was attached to the ventral wall of 

 the abdomen by a ventral mesial mesentery composed of peritoneum, which, as formerly 

 described, closely invested the bladder except on its pubic aspect. The apex of the 

 bladder extended to the umbilicus, where it still presented an open lumen. There was 

 no obliterated part or urachus, and throughout its entire length it presented a uniform 

 calibre, suggestive of an empty portion of small intestine. Developmentally, it may be 

 said to represent an enlarged and patent allantois ; but as this animal was only two days 

 old at the time of its death, probably a sufficient period had not elapsed for the closure 

 of the umbilical end of the organ. 



The hypogastric arteries were carried along each lateral aspect of the bladder, 

 suspended in peritoneal folds half an inch in width, so that these arteries were not in 

 contact with the wall of the bladder until they reached a point between 2 and 3 inches 

 from the umbilicus, where the peritoneal folds disappeared, and the arteries closed in 

 upon the sides of the bladder. 



The length of the bladder from the umbilicus to the prostate gland was 10 inches. 

 The prostate gland lay close to and on the abdominal side of the symphysis pubis. 



The interior of the bladder was lined by a mucous membrane, presenting numerous 

 rugosities, which to a large extent lay parallel to each other, and in the longitudinal 

 axis of the bladder. Towards the outlet the mucous membrane became comparatively 

 flat and smooth. 



The orifices of the ureters were longitudinal oblique narrow slits 2 mm. in length and 

 5 mm. apart. The lateral margins of each of these openings were continued towards 

 the outlet as slight ridges for a distance of 10 mm. These ridges met in the mesial 

 plane, thus forming a mesial longitudinal ridge or uvula vesicse. The actual trigonum 

 vesica? was therefore a triangular area 5 mm. wide at its base and 10 mm. long on 

 each side. 



The uvula vesicas was continued into the urethra, and became continuous with the 

 crista urethrse, which attained its greatest prominence 20 mm. from the apex of the 

 trigonum vesicse. The sinus pocularis was represented by a very small mesial aperture 

 opening on the distal side of the summit of the crista urethrse. 



The prostate gland did not attract attention, and at first sight one would have 

 doubted its presence. Certainly in cutting into the urethra from its pubic aspect no 

 variation in consistence was detected. Still, there was a definite thickening of the pubic 

 wall of the urethra corresponding to the general position of the urethral crest. On the 



(ROY. soc. EDIN. TRANS., VOL. XLVIII., 192.) 



