712 ORGANS OF DIGESTION. 



of the lower jaw. They are directed obliquely downwards and forwards. The 

 two central ones are larger than the two lateral, and their free edges are sharp 

 and chisel-like, being bevelled at the expense of their posterior edge : the root 

 is more rounded. 



The incisors of the lower jaw are smaller than the upper; the two central ones 

 are smaller than the two lateral, and are the smallest of all the incisor teeth. 



The Canine Teeth (cuspidati] are four in number, two in the upper and two in 

 the lower jaw ; one being placed behind each lateral incisor. They are larger 

 and stronger than the incisors, especially the root, which sinks deeply into the 

 jaw, and causes a well-marked prominence upon its surface. 



The crown is large and conical, very convex in front, a little hollowed and 

 uneven posteriorly, and tapering to a blunted point, or cusp, which rises above 

 the level of the other teeth. 



The root is single, but longer and thicker than that of the incisors, conical in 

 form, compressed laterally, and marked by a slight groove on each side. 



The upper canine teeth (vulgarly called eye-teeth) are larger and longer than 

 the two lower, and situated a little behind them. 



The lower canine teeth are placed in front of the upper, so that their summits 

 correspond to the interval between the upper canine tooth and the neighboring 

 incisors on each side. 



The Bicuspid Teeth (small, or false molars), are eight in number, four in each 

 jaw, two being placed immediately behind each of the canine teeth. They are 

 smaller and shorter than the canine. 



The crown is compressed from without inwards, and surmounted by two 

 pyramidal eminences, or cusps, separated by a groove, hence their name, licus- 

 pidate. The outer of these cusps is larger and more prominent than the inner. 



The neck is oval. 



The root is generally single, compressed, and presents a deep groove on each 

 side, which indicates a tendency in the root to become double. The apex is 

 generally bifid. 



The upper bicuspids are larger, and present a greater tendency to the division 

 of their roots than the lower : this is especially marked in the second upper 

 bicuspid. 



The Molar Teeth (multicuspidati, true, or large molars) are the largest of the 

 permanent set, and are adapted, from the great breadth of their crowns, for 

 grinding and pounding the food. They are twelve in number, six in each jaw, 

 three being placed behind each of the posterior bicuspids. 



The crown is nearly cubical in form, rounded on each of its lateral surfaces, 

 flattened in front and behind ; the upper surface being surmounted by four 

 or five tubercles, or cusps (four in the upper, five in the lower molars), sepa- 

 rated from each other by a crucial depression, hence their name, multicuspidati. 



The neck is distinct, large, and rounded. 



The root is subdivided into from two to five fangs, each of which presents an 

 aperture at its summit. 



The first molar tooth is the largest and broadest of all ; its crown has usually 

 five cusps, three outer and two inner. In the upper jaw, the root consists of 

 three fangs, widely separated from one another, two being external, the other 

 internal. The latter is the largest and the longest, slightly grooved, and some- 

 times bifid. In the lower jaw, the root consists of two fangs, one being placed 

 in front, the other behind : they are both compressed from before backwards, 

 and grooved on their contiguous faces, indicating a tendency to division. 



The second molar is a little smaller than the first. 



The crown has four cusps in the upper, and five in the jowcr jaw. 



The root has three fangs in the upper jaw, und two in the lower, the characters 

 of which :ire similar to the preceding tooth. 



The tliird molar tooth is called the wisdom tooth (dens sapientiee), from its late 

 Mppi-arance through the gum. It is smaller than the others, and its axis is 

 directed inwards. 



