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PHYSIOLOGY. 



two convoluted or, turbinated bones, of a light spongy tex- 

 ture, one being situated above the other ; and they divide 

 the general cavity of the nostril into three passages. 



2. In connection with the nostrils, there are several cavi- 

 ties, as in the frontal and upper jaw-bones, called sinuses. 

 These communicate with the nostrils, and as they extend 

 the surface on which the lining membrane is expanded, they 

 are supposed to contribute to the sense of smell, by affording 

 capacious receptacles for air, loaded with odorous particles. 

 Of the 14 bones which enter into the formation of the face, 

 11 assist in forming the cavities of the nostrils, as do also 

 three out of the eight bones that form the cranium. Be- 



Nasal fossae seen from behind, 



