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353 



in front of the true ones, and wliioh may be four in number; but these are 

 small teeth, having but littlo resemblance to the others, are most frequently 

 shed with the first deciduous molar, and are not replace. 1. 



"Generally considered, the molar arcades have not the same disposition 

 in both jaws. Wider apart in the superior one, they form a slight curvo, 

 win se convexity is outwards. In the inferior jaw, on the contrary, the two 

 parato in the form of a V towards the back of the mouth. Instead 

 of coining in contact by level surfaces, the molars meet by inclined planes, 

 and in such a way that the internal bonier is higher than the external 

 in the inferior molars, while the opposite takes place in the superior. 



" Like the incisors, each molar presents for study a free and a fixed 

 portion. 



" The free portion, nearly square in the upper molars, longer than wid<; 

 in the lower, shows at the external surface of the former two longitudinal 

 grooves, the anterior of which is the deepest, and which are continued on 

 the encased portion. This is not the case with the inferior molars, which 

 have but one narrow, and frequently an indistinct, groove. 



Pi?. IfiO. 



! ii.n OF rm: ri-riii: ri.i.ni o; in: H.. I.SI-UT M.I.V i\ii.\i'ii> n> 



snow rm. MOI.UIS: mi i \\<-> H \v: 

 a, Molar teeth; ft, Supplementary molar; <\ Tn>k ; -/, In. 



"The internal face in both jaws only shows one groove, and that hut 

 little marked; it is placed backwards in the upper molars, and is m.^t 

 apparent towards the root. 



t and posterior faces arc in contact with th < nding 



faces of the adjoining molars, except nt tin; extremities of the aread s, where 



1 into a narrow li.-rd<-r. 



NVitli regard to the table of the tooth, it inclines, as we have already 

 mentioned, outwards in the lower jaw. and inwards in the upper; a circum- 

 stance which prevents the lateral movements of the jnw< taking place with- 

 paration of the incisors, which s. -< m from friction." 



In the virgin molar this face is comp! mel. and 



ilarly undulated. In it may bo recognised the entrance to the two 

 infundibular openings, which are prolonged in the interier of the oi-L-an to 

 iity of the r.ot, nnd which are almost entirely tilled with cement 

 ri"d when the tooth lias ci.mpleted its evolution; they are only 

 he secretion of this crusta ]< In the tooth which has 



