246 STRUCTUEE AND ADAFIATION OF TEETH 



summer twilight, has a very peculiar effect. A 

 brief reference to this function may be desirable. 

 The term ruminant indicates the remarkable 

 faculty possessed by these animals, of re-mastica- 

 ting their food, which they return to the mouth 

 after previous deglutition, a power which results 

 from the structure of their stomachs, with four of 

 which they are always provided. The first three 

 of these stomachs are so arranged, that at the will 

 of the animal the food can be directed into either 

 of the three ; the oesophagus terminating at the 

 point of communication. The first stomach or 

 paunch, is much the largest, and serves as a 

 reservoir for the masses of herbage, rudely broken 

 up by the first mastication. These animals often 

 gather their food in great haste, and very greedily 

 devour rank growing herbage, a propensity which 

 frequently endangers the life of sheep and oxen, 

 when tempted by a luxuriant crop of green corn. 

 They eat so voraciously, that the first stomach 

 becomes over distended by the quantity of food 

 and the carbonic acid gas evolved from the vege- 

 table mass, and the animals, if not speedily 

 relieved, die of suffocation. 



Some special adaptations in the non-ruminant 

 ungulates will next demand our notice. 



In the horse, the incisors are present in both 

 jaws, and are slightly curved inwards ; the canines, 

 small in size, are developed in the male, and in 

 the upper jaw stand isolated in the wide gap 



