4 MAMMALIA. 



wliicli the animal lives. The teeth are divided into incisors, canines, 

 and molars. The last-mentioned are the most useful. In the Larni- 

 vora, they are sharp, and arranged in such a manner as to act like 

 the blades of a pair of scissors. In the Herbirora, they are flat and 

 roug-hish. In the Insectivora, they arc armed with little points, 

 which fit into each other. The canine teeth, indispensable to the 

 Carnivora for tearing- up their prey, assume sometimes a consider- 

 able development, and form what are called the tusl^s, as in the 

 wild Boar and some other animals. The tusks of the Elephant are 

 nothing else but the prolongation of the canine teeth, projecting 

 from the mouth. In the Whale, the teeth are replaced by flexible 

 blades, furnished with hair, and fixed firmlj^ to the jaw : these 

 are called tha whale-hone plates or lamince (baleen).* Certain genera 

 OL Edentata are also toothless, as the Ant-eaters and the Pangolins, 

 and again the Monotreniata. 



The upper maxillar}' bone, which forms the jaw, is immovable 

 in the Mammalia. 



AVhilst the aliments ai'e undergoing mastication, thej^ are satu- 

 rated with a liquid called saliva. The apparatus which fm-nishes 

 this liquid is composed of three glands — parotid, sublingual, and 

 siibina.rillari/. The saliva varies in its amount of development 

 accoi'ding to the kind of food "\^diich is taken. It is very highly 

 developed in the aquatic Mammalia. 



The deglutition is effected by the pharynx and the oesophagus, 

 which serve as a conduit for conve;\'ing the food into the stomach. 



All the Mammalia have but one stomach, with the exception 

 of the Rmninantia, which have four. The first and largest is 

 called the paunch; it occupies a great part of the abdomen. The 

 food stays there but a short time, passing thence into the bonnet 

 (honcy-cond) bag), or second stomach. This second stomach of the 

 Ruminantia is a little cavity which is in front of the paunch, and 

 which receives from that reservoir the alimentarv matter. After 

 having saturated it with the macerating juices, it sends it back 

 again to the a?sophagus, and thence to the mouth, in order that it 

 may undergo a second mastication. The food now descends 

 into the third stomach, which has received the name of feuillet or 

 /«(/ (m.anjr-plies), on account of the broad longitudinal folds with 



*But the ffptal whale has the rudinicnta of teeth, each providr,! y,\\^ jj-g pjoioer 

 nerve and hlood-vessels ; a most noteworthy adherence to the general tvije 



