Haevk^L ^ History of Crealwn. 



Skull-less 



[d crania) 



Single 

 nostrilled 



Ofonoirliinal 



j\yi^j]^^; jraired-nostrilled forms or Aiplurrhina 

 ' Tvith^lls, without Amnion. 



Amniota ' Paired nostrilled or Amphirrhina 

 ' with Amnion, without gills. 



Back-boned Animals 



based oiiPaleeoiitology. 



^ 



J 



