226 THE VISCERAL ANATOMY OF THE GROUND-RAT. 
The bile and pancreatic ducts open by an orifice 2 inches from the 
pylorus, and another a few inches further down. 
In the large intestine the cecum is 8 inches in length, and the 
intestine itself an inch over 4 feet. It is peculiar amongst the allied 
Rodents in that the cecum and colon are directly continuous, no 
abrupt change of direction occurring at the junction with the ileum ; 
and what is more, the sacculation on two longitudinal bands observed 
through the whole length of the cecum is continued for some distance 
along the colon, without any marked change of character except size. 
However, the two longitudinal bands which sacculate the cxcum are 
not those which do the same to the colon ; for opposite the ileo-czcal 
valve, which is a simple projection of the small into the large intestine 
for one sixth of an inch, much like that in the horse, one of the czecal 
bands splits into two, part going to join the other band, and part 
continuing on as an independent band. The small intestine joins the 
large, not, as is sometimes the case, at one of the bands, but in the 
middle of one of the sacculi, halfway between two of them. The 
diameter of the colon is less than that of the cecum, and diminishes 
gradually till it becomes scarcely greater than that of the ileum. The 
sacculation continues, getting less and less marked, for about a foot 
from the ileo-cecal valve; and the rest of the long colon is uniformly 
cylindrical, presenting the well-known abrupt bend near the middle of 
its course. 
The caput of the cecum is situated in the right lumbar region, 
and the base in the left lumbar, where an abrupt bend backward 
occurs, just before the small intestine enters. The omentum is not 
large, and does not cover the viscera. There is little or no fat in the 
abdomen. 
On opening the cecum and large intestine along its non-mesen- 
teric longitudinal band, two strongly marked longitudinal ridges are 
seen to run from the ileo-ceecal valve along the colon, one on each side 
of the inner surface of the mesenteric longitudinal band, which is the 
compound one formed by one division of the bifurcate cecal longi- 
tudinal band and the other cecal band. These ridges diverge at first 
and are afterwards separated by an interval of two thirds of an inch. 
For the proximal diverging 2 inches they are simple; but after that 
they are puckered regularly in exactly the same way as M. A. Milne- 
Edwards has figured the gastric cardio-pyloric ridges in Lophiomys, 
which they also resemble in general direction and arrangement. 
These puckered ridges, after diverging, again approach till within 
one fourth of an inch of one another, after which they continue 
parallel for a little more than 2 feet, where, just after the sharp colic 
bend, they suddenly cease, joining one another just before doing so. 
Page 788. The puckering, however, does not continue the whole way, it gradu- 
