122 ELEMENTS OF MAMMALIAN ANATOMY. 



The small projection at the lateral anterior angle is the 

 protostyle. The root of the tooth usually consists of 

 three fangs. The posterior tooth in the maxilla is 

 called the molar, since it is the only one not preceded 

 by a milk tooth. It is very small and its crown presents 

 a grinding surface instead of a cutting one. Its root 

 consists of two fangs. 



Each half of the mandible holds three incisors, one 

 canine, two premolars, and one molar. The incisors and 

 canine are so similar to the upper ones that they need 

 no further description. The first premolar presents a 

 principal cusp or protoconid, a lower small cusp or 

 metaconid, and a projection, on the posterior side of 

 the base, known as the talonid. A cingulum or encircling 

 ridge is also present at the base of the tooth. The root 

 consists of two fangs. 



The second premolar is very similar to the first except 

 that it is larger and presents an anterior basal cusp in 

 addition to the others. The lower molar, sometimes 

 called the sectorial, because it shears against the upper 

 sectorial or carnassial premolar, presents two nearly 

 equal cusps, the protoconid and the paraconid. The 

 root consists of two fangs, the anterior of which is the 

 larger. 



The deciduous or milk teeth begin to appear above the 

 gums when the kitten is two weeks old. The incisors 

 and the canine appear first, then the second and third 

 molars. The first upper molars do not appear till the 

 kitten is about six weeks old. According to Jayne, the 

 deciduous dentition is complete at the end of the second 

 month. At the end of the fourth month the milk incisors 

 are being displaced by the permanent teeth. The 

 formula for the temporary set is di f , dc J-, dm f . 



Teeth are present in nearly all adult mammals. The 



