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MAMMALIAN ANATOMY 



VARIATIONS IN THE PALATINE BONES. 



VARIATIONS IN SIZE. 



The following measurements of the palatines have been taken on 

 bones from the left side of the skull : 



The maximum length is the distance from the most prominent 

 point of the anterior edge of the horizontal plate to the most promi- 

 nent point of the posterior edge of the sphenoidal process projected on 

 a line parallel with the median border of the bone. 



The maximum width is taken, transversely to the preceding 

 measurement, from the median border of the horizontal plate to the 

 outer edge of the hook on the maxillary process. 



The length of the horizontal plate is the distance along the median 

 border from the tip of the postnasal spine to a point projected as far 

 forward as the most prominent point of the anterior border. 



The height of the vertical plate is the distance from the outer edge 

 of the tip of the maxillary hook to the upper edge of the ethmoidal 

 process at a point just behind the spheno-palatine foramen. 



VARIATIONS IN FORM AND DEVELOPMENT. 



The horizontal plate may be narrow and prolonged forward far 

 beyond the vertical process ; it may be wider, shorter, and more nearly 

 quadrate. Its inferior surface near the posterior external angle is not 

 infrequently marked by a strong tubercle. The lower openings of the 

 posterior palatine canals exhibit variations. In some specimens there 

 is a single large foramen in the anterior border, or just behind it; in 



