66 MR. R. OWEN ON THE STOMACH OF SEMNOPITHECUS. 
Ft. In. Lin. 
Length along the greater curvature, beginning at the left extremity 2 7 0 
Length along the lesser curvature. . . ees Ll OO 
Greatest circumference (a little to the right ar the sorden eel 40! 
Smallest circumference (at about two inches from the pylorus) . . 3 8 
This stomach may be regarded as consisting of three divisions: Ist, a cardiac pouch, 
with smooth and simple parietes, slightly bifid at the extremity; 2nd, a middle, very 
wide and sacculated portion ; and 3rd, a narrow elongated canal, sacculated at its com- 
mencement, and of simple structure towards its termination. The latter division, from 
its greater vascularity and the more abundant distribution upon it of the nerves of the 
eighth pair, I regard as the true digestive stomach; the preceding divisions appear 
to be preparatory receptacles or reservoirs. 
The esophagus enters into the left or cardiac division, which is separated from the 
middle division by a well-marked constriction. The diameter of this aperture of com- 
munication, when the stomach has been forcibly dilated, does not exceed 2 inches: 
so that-it seems highly probable, when no distending force is operating at this part, 
that the circular fibres which surround the constriction may, by the act of contrac- 
tion, render the separation complete, and thus form the cardiac pouch into a distinct 
cavity. A similar tendency to a separation of the cardiac from the pyloric moiety 
of the stomach has been observed to exist, in a greater or less degree, in stomachs 
of a much more simple structure, as in those of Man and of the Carnivora. It is, pro- 
bably, the possession of this power, in a greater degree, that enables some men to 
regurgitate at will a small portion of the contents of the stomach, or to ruminate. 
Such an action is therefore still more likely to take place, occasionally at least, in ani- 
mals which possess the complicated stomach here described: and there is a provision 
in these stomachs for the passage of ruminated food, or such as is of a fluid or easily 
digestible nature, directly into the second or sacculated division. 
A ridge is continued along the pyloric side of the cardiac orifice obliquely to the fold 
in the middle division, which is situated next beyond the constriction : a second ridge 
is continued from the right side of the cardia into the lower part of the septum that 
separates the cardiac from the middle compartment: and consequently between these 
ridges a shallow canal is continued from the esophagus to the middle division of the 
stomach. Supposing the circular fibres which form the two ridges to contract simul- 
taneously with those forming the constriction above, then the communication between 
the esophagus and middle division of the stomach would be cut off; but, on the other 
hand, if these fibres were relaxed, the food, and especially liquid food, would pass along 
the oblique canal directly into the middle compartment. 
Longitudinal fibres are continued from the esophagus upon the cardiac division ; but 
they gradually converge towards its left extremity, and there begin to be collected into 
the narrow band which traverses nearly the whole of the greater curvature of the stomach. 
