BY W. J. McKAY 915 



inferior surface is the alveolar border supporting a number of 

 small recurved teeth. The anterior extremity articulates with the 

 palate by a ginglymus joint. The posterior two-thirds of the bone 

 is twisted on its long axis, so that the interior surface comes to 

 lie internally, and slopes from above, downwards and inwards. 

 To this surface is attached the pterygo-sphenoid muscle, while the 

 parieto-pterygoid is inserted on the external border. The trans- 

 verse joins the bone at the junction of the anterior with the middle 

 half of the external border. The inferior surface is deeply 

 excavated, and gives attachment to the internal pterygoid muscle ; 

 while a number of small teeth spring from the inner border of 

 the surface. 



The posterior extremity of the bone comes to a point, from 

 which a ligament springs which connects the bone with the inner 

 side of the articular. This connection is not an intimate one, and 

 we can find no such arrangement of the extremity of the ptery- 

 goid, such as Huxley has described in Crotalus. This point will 

 be dealt with below. 



Os Palatinum. 



Os Palatinum^ all authors. 



The palatine is a prism-shaped bone slightly longer than the 

 maxilla. In the posterior half of its upper border is attached 

 the parieto-palatine muscle. . To the middle of this border the 

 maxilla is attached by ligament. The inferior border carries five 

 solid teeth almost the same size as those on the posterior part of 

 the maxilla. The external border fits into the groove on the 

 antero-lateral surface of the maxilla. The posterior extremity 

 articulates by a ginglymus joint with the pterygoid. 



The bone difiers but slightly in any of the forms examined. 



Hyoid Bones. 



The osseous portions of the hyoid bones are represented by two 

 thin bars which run forward on either side of the posterior portion 



