88 



THE SKFJ.ETOX 



The luandibular canines have not sueh pronounced features as the maxillary; 

 the i)<)int is hhmter. and the median ridge is absent from the lin<>;ual surface. 



The maxillary premolars or bicuspids. — The crown of the first i)remolar 

 has a ^'rinding surface which is somewliat (quadrilateral in outline; the lal)ial is, 

 however, longer tlian the lingual border. It has two cusps, of which the laljial is 

 much' the larger. The cusps or tubercles are separated by a pit, but are connected 

 l)v a narrow ridge along the median and distal l^orders. The median border is 

 nearly straight, the distal is convex. The root may be single or it may l)e bifur- 

 cated near the apex or marked by a longitudinal depression, or lie double through- 

 out the greater part of its length; it may in some specimens have three distinct 

 roots like a molar. 



The second bicuspid differs from the first in having its cusps nearly equal in 

 size. Its root is more deeply grooved. 



The mandibular bicuspids are smaller than the upper and differ from them in 

 shajH'. The labial cusp is larger than the lingual; the cusps are connected by a 

 low ridge, the grinding surface presents two small ])its. The root is single, rounded, 

 and tapering. 



The second lower bicuspid is larger than the first. The labial cusp is higher 

 and stouter, and the distal border is much more pronounced. Its root is also 

 single and tapering. 



The maxillary molars. — The first and second resemble each other so closely 



Fiu. 95.— The Temporary Teeth. 



INCISORS CANINE MILK MOLARS 



■^Wtm MAXILLARY OR UPPER SET 



MANDIBULAR OR LOWER SET 



that one description will serve for the two. The grinding surface is quadrilateral 

 l)ut with rounded angles. It has four cusps, two buccal and two lingual. Of 

 these, the anterior lingual is the largest, and is connected with the posterior buccal 

 by an oblique ridge of enamel. The groove separating the buccal and lingual cusps 

 extends on to the sides of the croAvn and is lost near the neck. The median and 

 distal borders usually present a slight ridge. The roots are three in number, two 

 on the labial, and one on the palatine aspect; this last is usually referred to as the 

 palatiiif r(»nt, ;md often diverges from the crown at a considerable angle. 



The mandibular molars. — The first is the most constant in form. It has five 

 cusps on the grinding surface. Four occupy the angles and are separated by a 

 crucial fissure. The fifth cusp is situated at" the posterior extremity of the longi- 

 tudinal fissure. It has two roots, placed one in front of the other; they are 

 inclined somewhat backwards, and present a vertical groove which is sometimes so 

 deep as to divide each root, producing four roots. One root only may divide in 

 this way. 



Tlie second molar differs from the first in the frequent absence of the fifth 

 cusp; when present it is feebly developed. The roots have a tendency to become 

 conHucnt. 



The third molars (wisdom teeth). — The upper third molar resembles in its 

 grinding surface tlie adjacent molars. The two palatine tubercles are usually 



