4 A MANUAL OF DENTAL ANATOMY. 



vantageous introduction to the subject, as he must neces- 

 sarily already possess some knowledge of their forms, while 

 to the matters alluded to in the preceding pages more full 

 reference will be made hereafter. 



XIn the human subject no tooth rises above the level of 

 its fellows, and the teeth are arranged in close contact, with 

 no interspaces between them. The teeth are ranged around 

 the margins of the jaws in a parabolic curve, or something 

 approximating to one ; in the lower races of mankind the 

 curve tends to a squarish, oblong form, owing to the 

 prominence of the canines (compare the figure of the denti- 

 tion of Simia Satyrus), whilst a deviation in the opposite 

 direction is daily becoming more common in the most 

 highly civilised races, resulting in a contour to which in 

 extreme cases the name of V-shaped maxilla is applied. 



It may be stated, as generally true, that the teeth are 

 somewhat larger on their labial than on their lingual aspect, 

 a result which necessarily follows from their standing with- 

 out interspaces along a curved line. And as great variations 

 in size and shape, as well as in colour, are found to exist 

 between different individuals, it is only possible to give 

 such a description as shall apply to the generality of teeth. 



The teeth of the upper jaw are ranged along a curve of 

 larger dimensions than those of the lower, the incisors pass- 

 ing in front of the corresponding lower teeth, and the ex- 

 ternal cusps of the bicuspids and molars closing outside 

 those of the lower teeth. 



There are, however, some points of detail to be noted in 

 the relation borne by the upper to the lower teeth, besides, 

 that comprised in the general statement that the former lie 

 outside the latter, by which it is brought about that each 

 tooth is antagonised by portions of two teeth in the other 

 jaw, and has not only a single opponent. 



The upper incisors and canines, when the mouth is closed, 

 from the larger size of the arch in which they are arranged, 



