914 THE OSTEOLOGY AND MYOLOGY OF THE DEATH ADDER, 



The transpalatine is an irregularly shaped bone, about half the 

 length of the pterygoid. Viewed from above it is seen to be 

 convex externally ; viewed from the side the anterior half is 

 so curved that the convexity is above. The anterior extremity 

 is flattened from above downwards, and presents an articular 

 head for the maxilla, the external portion being convex, the 

 internal concave. The superior surface is convex, while a deep 

 fossa occurs on the inferior. To the superior surface is attached 

 a well marked band of fascia running from the postorbital bone 

 above, which serves to bound the orbit, suspend the transpala- 

 tinum and limit its anterior movement, and lastly to form a floor 

 for portion of the venom gland to rest on. At the j unction of the 

 anterior with the posterior half of the inferior surface, there 

 springs a strong recurved process. To this, as well as to the 

 posterior half of the inferior surface, the lower head of the 

 internal pterygoid muscle is attached. The posterior extremity, 

 as well as portion of the internal surface, articulates with the 

 pterygoid bone. 



The chief point in connection with this bone is the prominent 

 recurved process of the inferior surface. In some lizards we have 

 observed a somewhat similar process. It is also to be observed 

 that the insertion of the pterygoid muscle into this bone is one of 

 the reasons for considering that Acantlioiihis is far removed from 

 the vipers. 



Os Pterygoideum. 



Pterygoideum externum, D' Alton, Harting ; Pterygoid, Cuvier, 

 Gegenbaur, Huxley, Hofimann, Joh. Muller, Owen, Parker, 

 Parker and Bettany, Stannius, Rathke, Wiedersheim ; Yorderes 

 FlUgelstilck des Keilbeins, Meckel. 



The pterygoid is a scimitar-shaped bone, and thrice as long as 

 the palatine. The anterior third is prism-shaped with its external 

 side slightly convex, while the posterior two-thirds is flattened 

 from above downwards, with a well marked concavity externally. 

 The superior surface of the anterior portion of the bone gives 

 insertion to a few fibres from the parieto-palatine muscle. The 



