51.2 Proceedings of Royal Society of Edinburgh. [sess. 
a sharp bend by which it is continued into the next part of the 
colon. This curve is in contact with the right lateral lobe of the 
liver. In calibre the ascending colon is, at first, about equal to 
the caecum ; but it narrows slightly as it passes onwards. 
The succeeding parts of the colon are so ordered that there is no 
possibility of receiving assistance from the terms used in human 
anatomy. It seems convenient, on the other hand, to give the 
various parts a literal designation, without in any way en- 
deavouring to compare them with the parts of the human colon. 
When the colon has formed the sharp hepatic flexure above 
mentioned, there follows a part which we may refer to as A (PL I. 
fig. 2), running towards the pelvis, ventral to the ascending colon 
and to the right of the mesial plane. After a course of about 
65 mm. a sigmoid curve is formed by the intestine turning 
abruptly over to the left and, at the same time, inclining dorsal- 
wards ; and then as suddenly bending towards the pelvis. This 
double curve brings the colon almost into the middle line of the 
abdomen, and takes place a little above the level of the termination 
of the ileum. The next stretch of intestine we will call B. It is 
about 140 mm. long, and passes almost straight caudal wards to 
the entrance to the pelvis. Here there is another sudden change 
of direction. This time the bend is dorsalwards and to the left, 
and leads to a length of colon marked C in the figures. A certain 
portion of C can he seen without any disturbance of the small 
intestine ; hut this part of the intestinal canal must he removed 
before the further course of the colon is visible. C is found to 
run cephalwards, and in contact with the wall of the abdomen on 
the left side, for a distance of 130 mm. ; then there is a series of 
twists which results in the production of a piece of intestine which 
may he said to resemble a horse-shoe in form. The curves, etc., 
are as follows : — C ends by turning abruptly cephalwards, so that 
the next short segment of the colon lies dorsal to C. Then there 
is a turn ventrally and somewhat to the right, and the colon again 
becomes visible as the animal is lying on its back. Finally there 
is a turn directed cephalwards and to the left (PI. II. fig. 4). 
After this series of twists comes a short, narrow part of the colon 
which runs cephalwards and obliquely to the right to gain the 
mesial plane of the body, where there is a final sudden turn at 
