510 Proceedings of Royal Society of Edinburgh. [sess. 
pylorus represents the pyloric canal. But there is no distinction 
between a body and a pyloric antrum such as is shown in 
Semnopithecus. With the evidence at our disposal we can only 
conclude, provisionally, that in Cercocebus these two portions are 
undifferentiated to the naked eye, and that they form the major 
part of the tubular segment. It is to he regretted that the 
animal had been dead for some little time before it came into my 
]30ssession. Had it been possible to make reliable microscopic 
sections of the different parts of the stomach, much more definite 
conclusions could have been arrived at. Sections have been made, 
but, on examination, it is found that post-mortem changes are too 
extensive to permit of any statement being made which would be 
of any value. 
Small Intestine . — As previously stated, the pylorus points 
towards the dorsum of the animal. From it the duodenum passes 
in a curved direction caudalwards, the concavity of the curve 
looking ventralwards and towards the pelvis. This part of the 
duodenum inclines (but not markedly so) towards the left, and so 
it arrives in the mesial plane of the body, where there is an 
abrupt bend ventralwards and cephalwards. The second part of 
the duodenum is short and inclined to the left. The duodenum, 
as here described, is recognised as that part of the small intestine 
that is without a mesentery. Its total length is about 90 mm. 
On opening it the common opening of the bile and pancreatic 
ducts is found at a distance of 75 mm. from the pylorus, i.e ., 
these canals open into the first part of the duodenum as here 
described. 
The remainder of the small intestine is located almost entirely 
to the left of the mesial plane, and measures some 286 cm. in 
length when freed from its mesentery and laid out straight on a 
table. When the abdomen is first opened and the great omentum 
has been removed, only a little of the terminal part of the ileum is 
visible ; the rest of the small intestine being hidden by the colon 
and the mesocolon (PI. I. fig. 2). The calibre of the tube is fairly 
uniform. There are no valvulse conniventes, and Peyer’s patches 
are extremely difficult to recognise. 
Caecum . — This is a short curved tube, of considerable diameter, 
whose apex is blunt and points to the left, and is, therefore, not 
