OSSA MAXILLARIA SUPERIORA. 87 



posterior to this ridge is concave to accommodate the lachrymal 

 sac. 



The orbitar plate, which covers the great cavity, and forms 

 the bottom of the orbit, is rather triangular in form, arid con- 

 cave. In the posterior part is a groove or canal, which pene- 

 trates the substance of the bone, as it advances forward, and 

 terminates in the infra-orbitary foramen, below the orbit. At 

 the place where this plate joins the nasal process above men- 

 tioned, viz. at the inner angle of the orbit, is the commencement 

 of the bony canal, which transmits the lachrymal duct into the 

 cavity of the nose. 



The malar process projects from the external and anterior 

 corner of the orbitar plate ; it supports the malar bone, and is 

 rough for the purpose of articulating with it. 



The alveolar processes compose the inferior and external 

 margins of the upper maxillary bones. When these bones 

 are applied to each other, they form more than a semicircle : 

 their cavities contain the roots of the teeth, and correspond 

 with them in size and form. They do not exist long before 

 the formation of the teeth commences ; they grow with the 

 teeth ; and when these bodies are removed, the alveoli dis- 

 appear. 



The palate process is a plate of bone, which divides the nose 

 from the mouth, constituting the roof of the palate, and the floor 

 or bottom of the nostrils. It is thick where it first comes off 

 from the alveolar process ; it is thin in its middle ; and it is 

 again thick where it meets its fellow of the opposite side. At 

 the place where the two upper jaw bones meet, the palate plate 

 is turned upwards, so that the two bones are opposed to each 

 other in the middle of the palate, by a broad flat surface, which 

 cannot be seen but by separating the bones. This surface is so 

 very rough, that the middle palate suture almost resembles the 

 sutures of the skull ; and the maxillary bones are neither easily 

 separated, nor easily joined again. The meeting of the palate 

 plates by a broad surface, makes a rising, or sharp ridge, 

 towards the nostrils ; so that the breadth of the surface by 

 which these bones meet, serves a double purpose ; it joins the 



