692 



MAMMALIA 



[CH. 



Ruminantia. 



When we leave the Pigs we have to deal with the higher 

 section of the Artiodactyla, the SELENODONTIA or 

 JRUMINANTIA, which include most of our domestic 

 animals, the Cow, Sheep, Goat, Camel, etc., as well as all the Deer 

 and Antelopes. The latter name is derived from the habit of ruminat- 

 ing, that is of bringing the food back from the stomach into the 

 mouth after it has been swallowed and chewing it again. Correspond- 

 ing to this habit we find that the stomach has acquired a complicated 

 structure. Just where the gullet opens into it we find a large pouch 

 projecting laterally with the walls covered with little projections or 



FIG. 346. Stomach of a Sheep, cut open to show the various chambers. 

 Oesophagus. 2. Kumen. 3. Eeticulum. 4. Psalterium. 



5. Abomasum. 



6. Duodenum. 



papillae; this is called the paunch or rumen. Just below the 

 oesophagus is another smaller pouch divided by a constriction from 

 the first (Fig. 346). The second pouch is called the reticulum 

 because its walls are raised into intersecting folds producing cavities 

 like the cells of a honeycomb. The food mixed with saliva is 

 swallowed without chewing, and after traversing the oesophagus it 

 is driven from rumen to reticulum and back by the action of the 

 muscles and well soaked with gastric juice. After some time it is 

 pressed up again into the mouth and thoroughly ground up by the 

 great broad premolar and molar teeth. When swallowed for the 



