284 A MANUAL OF DENTAL ANATOMY. 



occupying the front of the lower jaw, of which the outer- 

 most pair are called canines, although not in the smallest 

 degree meriting that name for any other reason than that 

 they close in front of the caniniform tooth of the upper jaw, 

 for they are just like the other incisors. 



But it is in the Insectivora that the greatest difficulties 

 occur. 



To the mole no less than four dental formulae have been 

 assigned, all turning upon the identification of the canine. 

 The difficulty is this : The upper tooth, which looks like a 

 canine, has two roots, and is implanted (and its deciduous 

 predecessors also lie) (Spencer Bate) within the limits of 

 the premaxillary bone. And besides this, the lower tooth, 

 which answers the purpose of, and looks like, a canine, 

 closes behind instead of in front of the great upper tooth. 



FIG. 117 0. 



Nal~. Size. 



Erlculus has a sharp, long, two-fanged tooth, in pattern of crown, 

 an enlarged premolar, in position of upper canine, and no canini- 

 form tooth in lower jaw. 



Centetcs has typical canines, like a Carnivore. 



Ilemicentctvs, the so-called canine, differs in no respect from the 

 premolars behind it. 



Erinaceus. So called upper canine two-rooted, and like the pre- 

 molars which follow behind it. 



0) Upper and lower teeth of the common mole. In it, just as in 

 Oreodon, the teeth which fulfil the functions of canines are not corre- 

 sponding teeth in the upper and lower jaws. 



