880 MR. F. G. PARSONS ON THE [NoV. 29, 



caecal valve. The ileum opens into the csecum on its posterior 

 surface, but there is no sacculus rotundus (see fig. 10). 



Fig. 10. 



CsBOum of Pedetes viewed from behind. 

 A. Ileum. B. Cascum. C. Colon, 



The Gcecmn is a thin-walled sac of large calibre, 8 inches in 

 length. It is bent into a horseshoe loop, and round the con- 

 vexity of the horseshoe the colon lies, the two viscera being 

 bound together by areolar tissue and having no peritoneum 

 between them. The caecum ends bluntly, and there is no 

 appendix. When the caecum is opened the ileo-caecal orifice is 

 seen ; this is a transverse slit | inch long, capable, when fully 

 distended, of admitting a quill-pen. The valve which guards this 

 opening has, as usual, two lips, csecal and colic. The caecal lip is 

 the more prominent, and is prolonged halfway round the gut as 

 a shelf ; the colic lip does not extend so far. The mucous mem- 

 brane of the caecum has a number of transverse rugae ; these are 

 best marked opposite the posterior part where the vessels enter 

 and the peritoneal attachment is. The Colon is at first di'ated, 



