UNGULATA. 589 



the muscles of the oesophagus. After having been thoroughly 

 chewed and prepared for digestion, the food is swallowed for 

 the second time. On this occasion, however, the triturated 

 food passes on into the third cavity (/), which is variously 

 known as the " psalterium," " omasum," or (Scottice) the " many- 

 plies." The vernacular and the first of these technical names 

 both refer to the fact that the inner lining of this cavity is 

 thrown into a number of longitudinal folds, which are so close 

 as to resemble the leaves of a book. The psalterium opens 

 by a wide aperture into the fourth and last cavity, the " abo- 

 masum " (a), both appearing to be divisions of the pyloric 

 portion of the stomach. The mucous membrane of the abo- 

 masum is thrown into a few longitudinal folds, and it secretes 

 the true acid gastric juice. It terminates, of course, in the 



Fig. 252. Stomach of a Sheep, o Gullet ; r Rumen or Paunch ; h Honeycomb- bag or 

 Reticulwn ', p Manyplies or Psalterium ,' a Fourth Stomach or Abomasum. 



commencement of the small intestine i.e., the duodenum. 

 The intestinal canal of Ruminants, as in most animals which 

 live exclusively upon a vegetable diet, is of great relative 

 length. 



The dentition of the Ruminants presents peculiarities almost 

 as great and as distinctive as those to be derived from the 

 digestive system. In the typical Ruminants (e.g., Oxen, Sheep, 

 Antelopes) there are no incisor teeth in the upper jaw, their 

 place being taken by a callous pad of hardened gum, against 

 which the lower incisors impinge (fig. 253). There are also 

 no upper canine teeth, and the only teeth in the upper jaw 

 are six molars on each side. In the front of the lower jaw 

 is a continuous and uninterrupted series of eight teeth, of 

 which the central six are incisors, and the two outer ones are 



