468 



THE DIGESTIVE APPARATUS IN MAMMALIA. 



free border ; but In the interior of the groove it poasesses all the characters of the oesophageal 

 mucous membrane, in being smooth, white, and ridged longitudinally ; near the orifice of the 

 omasum it has some large conical papillae. 



If this membrane be removed to study the subjacent tissue, the following arrangement is 

 observed : At the bottom of the channel, and in the space comprised between its two lips, are 

 transverse muscular fibres, which belong to the rumen or reticulum. The lips themselves are 

 entirely composed of longitudinal muscular fasciculi, particularly abundant towards the free 

 border ; these fasciculi are mixed with the proper fibres of the stomach, towards the extremities 

 of the canal, and are carried from one lip to the other in forming loops around the orifices 

 which communicate by this canal. 



Omasum (Psalterium, Many-plies, Many-leaves, or Manyplus. Figs. 268, 270, 271).— In 

 the Ox, this compartment is larger than the reticulum, but in the Sheep and G-oat it is smaller, 



Fig. 271. 



stomach of the sheep (seen from the interior of the omasum). 



O, (Esophagus; P, rumen; R, reticulum; c, abomasum ; F, omasum opened at its large curvature, 

 the two portions being reversed forward and backward. 1, Opening between the rumen and 

 reticulum, surrounded by the extremity of the lips of the oesophageal furrow ; 2, opening between 

 the omasum and abomasum. i, Commencement of the small intestine. 



Situation — Form — Relations. — Situated above the cul-de-sac of the reticulum and tha 

 anterior extremity of the right sac of the rumen, this compartment, when distended, has an 

 oval form, is slightly curved in an opposite direction to the honeycomb division, and depressed 

 from before to behind. It has, therefore, an anterior face, applied against the diaphragm, to 

 ■which it is sometimes attached by connective tissue ; a posterior face lying towards the paunch : 

 a great curvature, turned upwards, and fixed in the posterior fissure of tlie liver by an omental 

 frsenum which is continued on the lesser curvature of- the abomasum and duodenum; a lesser 

 curvature, which looks downwards and responds to the recticulum ; a left extremity, exhibiting 

 the neck, which corresponds to the orifice of communication between the reticulum and omasum ; 



