VERTEBEATA 35 



Anterior vertebrae similar; a precoracoid 



arch and a coronoid bone ; (4) Ginglymodi. 



AA. No metapterygium ; anterior vertebrae modified, 

 and with ossicula ; vertebras amphicoelous. (Ostario- 

 physse). 



;9, A precoracoid arch. 



Y, No symplectic bone. 



Anterior vertebrte modified, and with ossi- 

 cula auditus ; pterotic simple ; parie- 

 tals not distinct ; (5) Nematognathi. 



JX, A symplectic bone. 



Anterior vertebrae coossified, and with ossi- 

 cula auditus ; pterotic simple ; parie- 

 tals distinct ; (6) Pledospondyli. 



j3j^, No precoracoid arch. 



Parietals present, distinct, not separated 



by supraoccipital ; (7) Glanencheli. 



AAA. No metapterygium ; vertebrae amphicoelous, 

 the anterior not modified and without accessory 

 ossicles. (Teleocephali). 



/5, Scapular arch suspended to cranium. 



«, A symplectic. 



;', A precoracoid arch. 



Pterotic annular, including a cavity which 

 is closed by a distinct bone ; parietals 

 distinct, not separated by supraoccip- 

 ital ; (8) Scyphophori. 



Pterotic simple; parietals distinct, not sep- 

 arated by supraoccipital ; (9) Isospondyli. 



Eight pectoral basilar bones, the external 



