INTERIOR 461 
(parietal) face of the omasum and the pyloric part of the abomasum and the first 
part of the duodenum. What might be regarded as a connection between the 
omenta is a fold between the ventral curvature of the omasum and the dorsal 
curvature of the abomasum. 
The greater omentum conceals the greater part of the intestine on the right 
side, with the exception of the duodenum, and covers the ventral sac of the rumen 
almost entirely. It is not lace-like, as in the horse, and contains a large amount 
of fat in animals in good condition. It may be described as consisting of two 
parts, each of which is composed of two layers of peritoneum; the two serous layers 
enclose a variable amount of fat. The superficial part extends from the left 
groove of the rumen ventrally around the ventral sac and ascends on the right 
side, covering the deep part. It ends along the retrograde part of the duodenum 
and the greater curvature of the abomasum. The deep part is attached along the 
visceral (right) surface of the rumen ventral to the right groove, and curves around 
the intestinal mass to the right side, where it is covered by the superficial part. It 
Fic. 393.— INTERIOR OF ABOMASUM OF OX. 
FP, Fundus gland region with large spiral folds; P, pyloric region; D, duodenum; 1, pylorus; 2, torus pyloricus. 
ends chiefly by blending with the medial layer of the mesoduodenum, but anter- 
| iorly is attached on the first bend of the colon and the visceral surface of the liver 
_ along the ventral border of the pancreas. The two parts are continuous at the 
| posterior groove of the rumen. They also join at the iliac flexure of the duodenum 
and at the origin of the colon. The epiploic foramen is almost sagittal in direc- 
tion. 
The muscular coat of the rumen consists of two layers. The fibers of the 
external layer are in general longitudinal; those of the thicker internal layer are 
| largely circular in direction. The latter forms the bulk of the chief pillars, where 
it is about one-half to one inch (ca. 1 to 2 em.) thick. Scattered bundles of striped 
muscle-fibers radiate from the cardia in the wall of the atrium and extend also along 
the cesophageal groove. 
The arrangement is in fact by no means so simple as might be inferred from the above brief 
statement, and much variation from the typical disposition is present. Along the furrows the 
)fibers of the external layer are disposed more or less obliquely or even vertically in part; a super- 
ficial part of the layer bridges over the furrows (with the fat and vessels contained therein), while 
the deeper fibers extend into the pillars. The fibers of the inner layer on approaching the furrows 
jchange to an oblique or even horizontal direction. On entering the chief pillars this layer becomes 
