ORGANS OF DIGESTION. 



121 



crown. The next three teeth are known as the pre- 

 molars. 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 distinction 

 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, 







FIG. 57. LATERAL ASPECT OF THE PERMANENT DENTITION OF THE CAT. 



i lt i, 2 , i { , First, second, and third incisors of the upper jaw; c, canine; />,, 

 p. 2 , and /> :i , first, second, and third premolars; m, molar; 1, 2, 3, the 

 incisors of the lower jaw; 4, canine; 5 and 6, first and second pre- 

 molars; 7, molar; c, cingulum; d, deuterocone ; m, metaconid; m, mo- 

 l.ir; pt, protoconid; re, protocone; td, talonid ; /, talon; tr, 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 central cusp, posterior to which is the large triti- 

 cone. At the mesal anterior angle is the deuterocone. 



