ORGANS OF DIGESTION. 109 



recent state the nerve- and blood-vessels. The enamel con- 

 sists mostly of the phosphate of lime. It is the covering 

 which when broken permits the tooth to decay. 



In an adult cat there are in each half of the upper jaw 

 three incisors, one canine, three premolars, and one molar 

 (Fig. 58). In each half of the lower 

 jaw there are three incisors, one ca- 

 nine, two premolars, and one molar. 

 The permanent dentition of the cat is 

 therefore expressed by the formula 

 i %, c %, pm %, m %. 



The upper incisor teeth are small and 



j. i j i .-, -, FIG. 57. LONGITU- 



undivided both as to root and crown. DINAL SECTION OF 



They are scarcely one-third as long THE CANINE TOOTH. 

 as the canine and are planted in the '^TeminefT^n- 



alveoli or sockets of the premaxillary. amel > f>. f an s > m > 

 rr^, . . .... pulp-cavity ; n, neck. 



I he remaining teeth of this jaw are in 



the maxilla. The canine or eye tooth is the longest and 

 likewise is undivided as to root and crown. The next three 

 teeth are known as the premolars. They vary much in size. 

 The anterior one is the smallest, being about the size of the 

 incisors. Its crown is usually simple, although occasionally 

 there is seen a small posterior cusp, called triticone, in dis- 

 tinction to the main cusp or protocone. The root is usually 

 composed of only one fang. The second premolar is much 

 larger than the first. Its crown presents a large median 

 cusp, or protocone; a very small cusp, triticone, on the 

 posterior side of the protocone half-way between its base 

 and apex; and a basal cusp, the talon, on the posterior side 

 of the base of the tooth. The prominent ridge encircling 

 the tooth at its base is the cingulum. The root is composed 

 of two fangs. 



The third premolar or carnassial tooth is fully twice as 

 large as the second premolar. Its protocone is the large 



