402 MAMMALIAN ANATOMY 



CHAPTEE VI 



THE TEETH 



The Teeth are usually described as parts of the digestive system ; 

 they are developed from papillae in the epithelium of the mouth, and 

 their relation to the skeleton of the face is a secondary one. They 

 are, however, so firmly planted in the jaw bones that they can be 

 properly examined only after the skull has been cleaned and macerated ; 

 hence it is more convenient to study them in connection with the 



t/ 



skeleton. 



At birth the teeth are still concealed in their sockets or alveoli. 

 If the gums be cut away, the edges of the jaws will exhibit an inter- 

 rupted furrow roofed by cartilage. When the kitten is two or three 

 weeks old the teeth begin to erupt through the gums, and usually 

 before it is forty days old the entire first set is in place. 



These first teeth are termed milk teeth ; they are developed during 

 the sucking period ; inasmuch as they fall out and are replaced by 

 a second set, they are more generally known as deciduous teeth. 

 They number twenty-six in all, on each side of the mouth thirteen > 

 whereof seven are on the upper jaw and six in the lower jaw. They 

 are divided into three groups : In front, above and below on each 

 side and placed transversely, are the three small deciduous incisors. 1 

 Posterior and lateral to these is the long, conical deciduous canine, so 

 named because of its prominence in the dog. It is sometimes termed 

 the laniary 2 tooth. On each side, behind the canine in the upper jaw 

 are three teeth, and in the lower jaw two teeth ; these ten teeth are 

 the deciduous molars. 3 It will be noticed that they differ in size and 

 in form, the first in the upper jaw being very small and separated 

 from the canine in front and the second deciduous molar behind by 

 diastemata. 4 



When the cat has reached the age of about four mouths, the de- 



1 Incidere, to cut into. 2 JJaniare, to rend. 



3 Mola, a mill. 4 Plural of diastema, an interval. 



