60 THE DISEASES AND DISORDERS OF THE OX. 



The paunch is the largest of the four oompartments in adult 

 life. It has a thick muscular coat. 



The surface of the rumen is divided into two hemispheres by 

 slight grooves wliich deepen towards the extremities. The sides 

 are smooth, thick, and rounded. The extremities are divided by 

 a deep fissure into two lobes. The two fissures mentioned divide 

 the rumen into a right and left sac. Of these the right sac is the 

 shorter and it is covered in the greater part of its extent by the 

 peritoneal omentum. The left is curved on the right at both 

 extremities, and above it receives the insertion of the oesophagus. 

 Anteriorly it is also continuous with the second compartment. 

 The anterior extremity has the second and third compartments 

 in front of it, and it lies near the diaphragm. The posterior ex- 

 tremity is contained in the brim of the pelvic cavity, where it 

 comes into proximity with the glinto-urinary organs. The 

 superior surface comes into relation with the intestines. The 

 inferior surface rests upon the floor of the abdominal cavity. 

 The left side has the spleen attached to it, and it is in contact 

 with, and attached by cellular tissue to, the wall of the lumbar 

 region of the abdomen. The right side is in relation with the 

 fourth compartment in the right hypochondriac and lumbar 

 regions, and it is embraced by coils of the intestines. 



On its internal surface the rumen is incompletely divided into 

 four sacs by fleshy pillars. The chief of these are the an- 

 terior and posterior, and they correspond to the two fissures. 

 Processes from these run from side to side and correspond 

 to constrictions on the outer surface. Hence, in front, the 

 right and left sacs are formed, and the right and left 

 conical sacs behind. The walls of the rumen, like those of the 

 other compartments, consist of three coats, an external serous 

 one, a continuation of the peritoneum which envelopes the 

 entire organ, with the exception of the place where it comes 

 into contact with the lumbar region. The middle coat is thick 

 and composed of muscle, and it is an extension from the oeso- 

 phageal fibres. The internal mucous coat is cuticular, papillated, 

 and covered with thick epithelium. These papillae are leaf-like, 

 conical, or fungiform, but those which are leaf-like are by far 

 the most numerous. The opening of the oesophagus into the 

 rumen and that of the rumen into the reticulum are both 

 situated at the anterior extremity of the left sac. The superior 



