THE FACE 353 



0, 2, 01 1, 2, 112 2, 2, 25 C, 2, 12 



0, 2, 1, 3 1, 2, 211 2, 2, C 2 C, 2, 2, 7 



0, 2, 26 1, 2, C 12 2, 3, C 1 C, 2, C, 16 



0, 2, C 6 1, 2, 04 2, C, 21 C, 3, C 2 



0, 3, 1, 2 1, 3, 1, 1 C, C, 1, 1 



0, 3, C 1 1, 3, C, 2 C, C, 21 



1, C, C-l 



The positions of the alveoli of a tooth may be slightly changed 

 when, as sometimes happens, the tooth is implanted in the jaw 

 obliquely to the long axis of the alveolar border. 



In two specimens examined there was no diastema between the first 

 and second premolars. 



It is difficult in some instances to distinguish between true varia- 

 tions and such abnormalities as result from disease. Two specimens 

 exhibited changes which may belong to the latter group. In one 

 the lachrymal opening was greatly increased in size, in fact equalling 

 the infraorbital foramen, and led into a large lachrymal canal, in 

 the outer wall of which an opening communicated with the canine 

 alveolus. In the other specimen the body of the maxillary contained 

 a true maxillary sinus which opened by an irregular foramen into the 

 nasal cavity in the fossa between the superior and inferior attachments 

 of the maxillo-turbinal. 



THE PREMAXILLARY BONES. 



General Description. The Prernaxillaries are median paired 

 bones, situated at the extreme anterior point of the skull (Fig. 273). 

 They lie on each side of the anterior nasal opening, and form the tip 

 of the upper jaw and complete the front part of the roof of the 

 mouth. In them are implanted the six incisor teeth. Each bone 

 consists of an inferior, thickened portion, the horizontal plate, or 

 body, from the upper surface whereof, at the outer part, rises a 

 curved ascending or nasal process, and from the posterior surface 

 whereof, at the inner side, springs a straight-pointed palatine process. 



The Body is a curved bar, and presents six surfaces. 



The anterior surface (Fig. 274) is about twice as wide as high, 

 strongly convex from side to side, and slightly concave from above 

 downward, producing the incisive fossa ; it faces outward and forward. 



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