THE ANATOMY OF THE OX. 63 



right extremity forms a round cul-de-sac, and it comes into 

 relation with the base of the fourth compartment. As regards 

 the interior, it is to be remarked that the internal surface of the 

 reticulum is divided into polyhedral cells by means of folds of 

 the mucous membrane, thus presenting the appearance of a 

 honeycomb. These folds have papillae upon them, and their 

 edges are serrated. These cells are further divided by secondary 

 partitions. Mucous follicles open on the internal surface. The 

 reticulum opens into the left sac of the rumen, and it also com- 

 municates with the oesophagus, and also with the psalterium. 



The communication with the oesophagus on the one side and 

 with the psalterium on the other is effected by the medium of 

 the oesophageal canal, a sort of continuation of the oesophagus, 

 which begins at the cardiac orifice, passes along the roof of the 

 reticulum, and enters the third compartment by a circular 

 opening. The sides of this canal consist of two movable lips, 

 the oesophageal pillars. They are continuous with the muscular 

 wall of the oesophagus and are attached by one border to the 

 superior wall of the reticulum, the other border being free. 

 As they approach the opening into the third compartment, they 

 gradually become thicker and project more markedly. At the 

 other extremity, where the canal enters the rumen, there is a kind 

 of valve which is formed by the attachment of the pillars to its 

 walls. The mucous membrane lining the free surface of this canal 

 is wrinkled ; but that which forms its internal surface is white and 

 folded longitudinally and resembles that of the oesophagus. Some 

 conical papillse are situated at its opening into the psalterium. 

 The canal is controlled by the action of transverse and longi- 

 tudinal muscular fibres. For example, we may point out that 

 the longitudinal fibres, by drawing the tips of the pillars together, 

 complete the formation of a channel leading from the oesophagus 

 into the manyplies, thereby quite closing up the openings into 

 the rumen and the reticulum. The third compartment is called 

 the omasum, or psalterium, or manyplies. It is situated at the 

 fore part of the right sac of the rumen. It is intermediate in 

 point of size between the reticulum and the abomasum. 



The food, after it has been remasticated, enters the third 

 stomach. The leaves present herein absorb the excess of 

 alkaline saliva, and so render the food drier for the abomasum. 

 The leaves are covered with villi. A hard and thick epithelium 



