OBSERVATIONS ON THE ANATOMY OF THE WEDDELL SEAL. 59 



The duodenum was suspended in a dorsal mesial mesentery whose base of attachment 

 measured nearly 5 inches, and this represented the distance between the pylorus 

 (gastro-duodenal junction) and the duodeno-jejunal junction which was situated close 

 behind (tail wards of) the superior mesenteric vessels and immediately to the left of the 

 mesial plane. To the right side of the duodenal mesentery there was a large peritoneal 

 recess whose right boundary was formed by a tailed lobe of the liver extending back- 

 wards along the dorsal wall in intimate association with the inferior vena cava. 



At the first glance there appeared to be no naked-eye distinction between the small 

 intestine and the colon. At no point were taenia coli, sacculations, or appendices 

 epiploicse visible. 



As measured from the duodeno-jejunal junction or flexure, 46 feet of gut were 

 suspended from the dorsal wall in a mesentery practically corresponding to the entrance 

 of the superior mesenteric vessels. A closer examination revealed a distinct lateral 

 diverticulum rather more than 1 inch in length but of the same calibre as the gut, 

 situated on that part of the gut, which was suspended in the mesentery and at a 

 point 9 inches from the hinder end of the mesentery. This diverticulum evidently 

 represented the ccecum and the vermiform appendix in their most primitive form, and 

 in the same condition as I have formerly described in the case of the grey seal 

 {Halichcerus grypus).* We may therefore conclude that this diverticulum marks 

 the commencement of the colon. 



Consequently the first 9 inches of the colon are suspended in the same mesentery 

 as the small intestine, exclusive of the duodenum. The remainder of the gut, i.e. colon, 

 was suspended in a dorsal mesial mesentery extending tailwards to the entrance of the 

 pelvis, while through the greater part of the pelvic cavity a dorsal mesial mesentery 

 supported the pelvic part of the colon, i.e. the rectum. 



The foramen of Winslow was very distinctly denned in relation to the free right 

 border of the gastro-hepatic omentum. Similarly the lesser sac of the peritoneum was 

 equally distinct, although the great omentum was not in any sense a gastro-colic structure. 



The inlet of the pelvis measured 1 inch in the transverse diameter and 3 inches 

 in the conjugate diameter. Its lateral boundaries were well defined by the hypogastric 

 (umbilical) arteries, each of which was supported in a peritoneal sling or ligament attached 

 to the dorsal wall along the pelvic inlet. 



The pelvic peritoneal pouch extended backwards between the gut and the bladder to 

 a distance of 3^ inches from the pubic crest, and so reached a point posterior to the 

 bulb of the urethra, i.e. to a point which corresponded with the central point of the 

 perineum. On the ventral abdominal wall, 1 inch to the outer side of the hypogastric 

 arteries, there was the opening which led into the inguinal canal (see fig.). Each 

 opening was circular and half an inch in diameter. It led into a circular peritoneal tube 

 which extended through the abdominal wall in relation to the hinder free border of the 

 musculus transversalis abdominis and the musculus obliquus interims abdominis. At 



* Hepburn, " The Grey Seal {Halichcerus grypus)" Jour. Anat. and Phys., vol. xxx. 



